Mobius Telephoto Dashcam

[c4rc4m]

I forget exactly where or when I said it, but not too long ago I mentioned that I thought 12mm was the optimal focal length for an ancillary telephoto dash cam. You seem to be confirming that.....and while I was composing this post, @Lola seems to agree too!

I think it's down to quality. Both are f2.0 so should exhibit similar DOF all things being equal, and TBH the DOF advantage on the 12mm isn't massive if you look carefully at the plates, just a bit more than the others. A longer focal length usually results in a shallower DOF. However, the glass looks a lot better. Much clearer and sharper. This is why I've often exerted the advantages of good glass. It really can make a difference. Out of the 3, the 12mm would be my choice simply on that basis. Any "excess" zoom is going to be compensated for by the wide angle anyway, so what's not capture on one should be captured on the other. I just wonder how f2.0 will perform at night especially if this lens was eg tried on a higher res mobius such as the Mxi.

 

[Harsh]

I just wonder how f2.0 will perform at night especially if this lens was eg tried on a higher res mobius such as the Mxi.

We'll find out soon. I have two each of the 8 and 12mm, plan on attaching the spare 12mm to the Maxi.

 

[TonyM]

12mm on M1 and 12mm on Maxi??

 

[Harsh]

12mm on M1 and 12mm on Maxi??

Yes

 

[Dashmellow]

I think it's down to quality. Both are f2.0 so should exhibit similar DOF all things being equal, and TBH the DOF advantage on the 12mm isn't massive if you look carefully at the plates, just a bit more than the others. A longer focal length usually results in a shallower DOF. However, the glass looks a lot better. Much clearer and sharper. This is why I've often exerted the advantages of good glass. It really can make a difference. Out of the 3, the 12mm would be my choice simply on that basis. Any "excess" zoom is going to be compensated for by the wide angle anyway, so what's not capture on one should be captured on the other. I just wonder how f2.0 will perform at night especially if this lens was eg tried on a higher res mobius such as the Mxi.

According to your logic all lenses of the same focal length and the same aperture will have the same depth of field and that is simply not true. And this ongoing fetish of yours about "good glass" is basically a weird fantasy at this point. Unfortunately, unlike high end name brand lenses costing thousands of dollars each we have no idea what sort of glass is used in these low priced commodity M12 lenses, so it's hardly worth speculating beyond the obvious notion that some are better than others.
What is of critical importance really is the optical formula devised by the engineers who designed the lens. While the "quality" of the "glass" is indeed important, many lens formulas employ lens elements of different types of glass and even of different materials. Nikon for example has produced some outstanding lenses that use both glass and plastic lens elements.

As for aperture, you can have two lenses of the same focal length and same aperture but one may perform better in low light than the other because of its design and optical coatings rather than "good glass".

 

[c4rc4m]

As I said above, all things being equal. Obviously the quality of the lens coating will be a factor on light transmission. A cheaper coating will usually block more than a quality coating.

With regards to the quality of the glass, there's a simple fact, it doesn't matter how good the sensor is if it's fed a poor picture. You could take the worlds best sensor, but if you put it behind a poor lens, you'll get a poor picture. Ultimately the primary limiting factor in any photo is going to be the quality of image fed to the sensor and that comes from the lens. Yes digital cameras are different from film cameras in that the sensor also plays much more of a part than film ever did, hence why the lens is only the primary factor, but the fact remains the sensor can only record the image that's fed to it.

So far as glass is concerned, yes plastic can be used, it's often clearer than glass although low iron glass takes away that advantage, and glass has less distortion than plastic. Again, why pro lenses tend to be glass and not polycarb. Then again, the ultimate is crystal - fluorite, which I doubt you're going to see on any dashcam lens anytime soon, this side of anyone making small dashcam lenses out off the off cuts. Super UD (Ultra low dispersion) glass is also probably in the same category albeit slightly cheaper. However, we should be less concerned with material than performance. No-ones saying on a dashcam we're going to notice the difference between eg fluorite and Super UD glass. However, at a back to reality level, we may see the difference between a cheaper glass lens and a higher quality glass lens for resolution, distortion and colour rendition.

 

[Lola]

As I said above, all things being equal. Obviously the quality of the lens coating will be a factor on light transmission. A cheaper coating will usually block more than a quality coating.

With regards to the quality of the glass, there's a simple fact, it doesn't matter how good the sensor is if it's fed a poor picture. You could take the worlds best sensor, but if you put it behind a poor lens, you'll get a poor picture. Ultimately the primary limiting factor in any photo is going to be the quality of image fed to the sensor and that comes from the lens. Yes digital cameras are different from film cameras in that the sensor also plays much more of a part than film ever did, hence why the lens is only the primary factor, but the fact remains the sensor can only record the image that's fed to it.

So far as glass is concerned, yes plastic can be used, it's often clearer than glass although low iron glass takes away that advantage, and glass has less distortion than plastic. Again, why pro lenses tend to be glass and not polycarb. Then again, the ultimate is crystal - fluorite, which I doubt you're going to see on any dashcam lens anytime soon, this side of anyone making small dashcam lenses out off the off cuts. Super UD (Ultra low dispersion) glass is also probably in the same category albeit slightly cheaper. However, we should be less concerned with material than performance. No-ones saying on a dashcam we're going to notice the difference between eg fluorite and Super UD glass. However, at a back to reality level, we may see the difference between a cheaper glass lens and a higher quality glass lens for resolution, distortion and colour rendition.

Making high quality glass is not rocket science, it's the finishing of the glass that pulls off minor miracles and that does take a very high level of equipment and workmanship and understanding. Last but certainly not least is the coatings and prescription for the coatings. It is generally considered that Japan has the edge on coating equipment.....at this time (coating recipes also). However we are not going to see this type of technology on M12 type lenses, the best we can hope for is the M12 lenses from China, very few of the manufactures I emailed in China even answered my emails, I really don't think they speak English, they hire what is called sellers, that is who we are dealing with when we buy China merchandise.

 

[country_hick]

If high quality glass is required to take good pictures and that good glass is hard to come by today please explain how civil war photos were taken back in the 1860's.
Manufacturing has come a long way in the last 150 years. What could not be done back then is easily done today.

 

[c4rc4m]

If high quality glass is required to take good pictures and that good glass is hard to come by today please explain how civil war photos were taken back in the 1860's.
Manufacturing has come a long way in the last 150 years. What could not be done back then is easily done today.

Resolution is much higher today with today's optics. A picture from the 1860's is relatively poor by today's standards.

Some things are still difficult from a cost pov. Fluorite for example has to be grown artificially as crystals as natural fluorite formations are too small and rare to be made into lenses. It is very difficult to machine - Canon had to invent their own process to make it possible without shattering the crystals and it then takes 4 times as long to polish as the nearest equivalent glass according to Canon. I wouldn't know about Super UD glass but would imagine both the glass (which I believe is fluorite impregnated) and the finishing process are far more expensive than say the glass in a consumer lens. So whilst tech has moved on, so have labour costs and some material costs making excellent glass very expensive.

That said, for our purposes there should be some some good glass available for far less than fluorite or Super UD glass. The main advantage of some of these extreme quality glasses is colour rendering far beyond what we need. As Lola points out, it is possible to manufacture more modest lenses that still have high resolving power and low distortion. Finding them in M12 and Mobius sensor sizing is a more harder task. I have spotted some in the past, but never in our sensor sizing on all but the most specialised and expensive retail sites.

That said, Dashmallow made a good point elsewhere, it's performance not paper stats that matter and as I also have pointed out, sometimes it's diminishing returns as well. The trick is to find a lens with fantastic real world performance at an acceptable price point. Also, as I pointed out once before, I believe resolution is everything and you get a better picture from a lens that resolves well above the sensors recording capability (high resolution = sharper better defined edges).

 

[Dashmellow]

As I said above, all things being equal. Obviously the quality of the lens coating will be a factor on light transmission. A cheaper coating will usually block more than a quality coating.

With regards to the quality of the glass, there's a simple fact, it doesn't matter how good the sensor is if it's fed a poor picture. You could take the worlds best sensor, but if you put it behind a poor lens, you'll get a poor picture. Ultimately the primary limiting factor in any photo is going to be the quality of image fed to the sensor and that comes from the lens. Yes digital cameras are different from film cameras in that the sensor also plays much more of a part than film ever did, hence why the lens is only the primary factor, but the fact remains the sensor can only record the image that's fed to it.

So far as glass is concerned, yes plastic can be used, it's often clearer than glass although low iron glass takes away that advantage, and glass has less distortion than plastic. Again, why pro lenses tend to be glass and not polycarb. Then again, the ultimate is crystal - fluorite, which I doubt you're going to see on any dashcam lens anytime soon, this side of anyone making small dashcam lenses out off the off cuts. Super UD (Ultra low dispersion) glass is also probably in the same category albeit slightly cheaper. However, we should be less concerned with material than performance. No-ones saying on a dashcam we're going to notice the difference between eg fluorite and Super UD glass. However, at a back to reality level, we may see the difference between a cheaper glass lens and a higher quality glass lens for resolution, distortion and colour rendition.

"All things being equal?" But they are NOT equal! Let's remember, you made that statement in reference to your notion that all lenses of the same focal length with an aperture of ƒ2.0 will have the same depth of field which is absolutely incorrect. Different lenses with different optical designs will perform differently even if they are of the same focal length and aperture. Case in point: Many of us spent a lot of time experimenting with 4mm ƒ/1.2 "Starlight lenses. They have a tendency to be difficult to focus and have a relatively short depth of field. In my case I purchased two different 4mm ƒ/1.2 "Starlight lenses from two different manufacturers. One was listed as an aspheric while the other didn't say. While both were quite similar they performed differently. One was slightly sharper across the field and offered greater depth of field than the other. Both, of course, were the identical focal length and aperture and were priced similarly.


You seem to have a strange habit of moving the goalposts when confronted with facts that don't support your dogma. So, now you are using that statement in regards to lens coating a glass types and ignoring my response to your previous post. And why even talk about Ultra low dispersion glass or fluorite? These things have nothing whatsoever to do with dash and action camera lenses. The fact is that unlike very specialized lenses from Canon, Nikon Schneider or Zeiss that cost thousands of dollars each we are using M12 lenses which are essentially a commodity item of varying quality and for the most part no way for the consumer to even know what types of glass are used in these lenses. "All things being equal" did not apply.
Of course this is what one learns from actually purchasing the lenses and working with them as compared to being an armchair pundit dispensing misinformation.

I believe resolution is everything and you get a better picture from a lens that resolves well above the sensors recording capability (high resolution = sharper better defined edges).

This is NOT true! While we do want high quality lenses in our cameras with good resolving power there is not only a point of diminishing returns in using higher than required resolving power lenses in our cameras but it can actually cause a deterioration in image quality if you go too high. Things are quite different than in the days of film based lens resolving power. For digital cameras, the lens MUST be matched to the size of the pixels. If you use a lens with too high a resolving power on a sensor with big pixels you will experience compromised results. There is a mathematical relationship between the LP/mm (Line Pairs per millimeter) resolving power of a lens and the size of the pixels. I've explained this to you before and provided authoritative resources for you to study but you apparently would rather live in some sort of pretentious fantasy about the highest resolution lenses being the ultimate goal, which it is not.

 

[c4rc4m]

In my case I purchased two different 4mm ƒ/1.2 "Starlight lenses from two different manufacturers. One was listed as an aspheric while the other didn't say. While both were quite similar they performed differently. One was slightly sharper across the field and offered greater depth of field than the other. Both, of course, were the identical focal length and aperture and were priced similarly.

The DOF is very dependent on the aperture, in fact it's the main controlling factor. I would suggest that differences seen could be down to small differences in aperture especially at the cheaper end of the market. A long focal length usually shallows DOF UNLESS the lens crops the subject to maintain the aspect in view.


On the fluorite subject, I used that as an illustration of the fact that some lenses materials and manufacturing methods are expensive, hence why very high quality lens aren't usually cheap these days despite modern manufacturing techniques. As for the material itself, personally I'd happily put fluorite in a dashcam if it were the right price. I'm not just interested in capturing accidents. Having a camera that will also double as a B roll camera is a definite advantage. Unfortunately fluorite is not cheap. Is Fluorite necessary? No. But it would be nice....

This is NOT true! While we do want high quality lenses in our cameras with good resolving power there is not only a point of diminishing returns in using higher than required resolving power lenses in our cameras but it can actually cause a deterioration in image quality if you go too high.

It might be diminishing returns, but some of us are willing to pay for extra quality. I concede there is a point where it doesn't make sense, both financially and in effect.

Things are quite different than in the days of film based lens resolving power. For digital cameras, the lens MUST be matched to the size of the pixels. If you use a lens with too high a resolving power on a sensor with big pixels you will experience compromised results. There is a mathematical relationship between the LP/mm (Line Pairs per millimeter) resolving power of a lens and the size of the pixels. I've explained this to you before and provided authoritative resources for you to study but you apparently would rather live in some sort of pretentious fantasy about the highest resolution lenses being the ultimate goal, which it is not.

No it mustn't necessarily match. You've seen this yourself with the Mobius 1 1080P 2.1MP vs the 5MP lens which showed significant image quality gains over the 3mp lens previously employed. This is where you're employing theory above practical usage.

Theoretically, what's more important is the relationship between the MTF (read contrast cycle) and the sensor cycle. It's probable the 5MP lens nearer matches that ideal which is why there's a visible improvement. I can't say I'm an expert on the theory, you probably know more theoretically than me here. However, as you pointed out above, it's not always about the theory...

 

[Harsh]

Back to the 8mm. Here's what I have the Mobius looking at while focusing.

 

[c4rc4m]

As you said when she came to the window.....nice bush!

 

[Dashmellow]

The DOF is very dependent on the aperture, in fact it's the main controlling factor. I would suggest that differences seen could be down to small differences in aperture especially at the cheaper end of the market. A long focal length usually shallows DOF UNLESS the lens crops the subject to maintain the aspect in view..

The fact of the matter is that different lenses with different optical formulas perform differently. You can have two lenses with the same focal length and the same ƒ-number that provide different amounts of DOF. It has nothing to do with you imagained notion that, "that differences seen could be down to small differences in aperture especially at the cheaper end of the market". As with so many of the pronouncements you make about optics this is pure fanatsy.

On the fluorite subject, I used that as an illustration of the fact that some lenses materials and manufacturing methods are expensive, hence why very high quality lens aren't usually cheap these days despite modern manufacturing techniques. As for the material itself, personally I'd happily put fluorite in a dashcam if it were the right price. I'm not just interested in capturing accidents. Having a camera that will also double as a B roll camera is a definite advantage. Unfortunately fluorite is not cheap. Is Fluorite necessary? No. But it would be nice....

Another pie in the sky fantasy that has nothing to do with M12 lenses, how they are manufactured or the markets for them.

It might be diminishing returns, but some of us are willing to pay for extra quality.

SOME of US?! You are not willing to purchase a single aftermarket lens to experiment with, even one of the very worthy modest prices ones that many of have been working with. Some of us? Who are you kidding?

No it mustn't necessarily match. You've seen this yourself with the Mobius 1 1080P 2.1MP vs the 5MP lens which showed significant image quality gains over the 3mp lens previously employed. This is where you're employing theory above practical usage.

Again, you haven't a clue. There are numerous reasons the 5MP varifocal zoom may perform well on the Mobius that are unrelated to resolution. In fact, the 3MP varifocal often often performs just as well to the point where you wouldn't be able to tell results apart from the 5MP 6-22m ƒ/1.6 or the 2.8-12mm ƒ/1.4 3MP. The fact is that there is literally no quantitative definition for what a "Megapixel lens" is. The term is marketing hype that is described as a hoax by major lens makers like Schneider Kreuznach optics. In these previous tedious discussions with you where you babble on an one about fancy "high megapixel lenses" I have provided resources for you to study which apparently you ignore in favor of living in a fantasy.

Don't get me wrong, there are crappy lenses, good ones and better ones on the market and indeed, they do make a difference but they need to be matched to the sensors they are use with. Each sensor has different sized and even different shaped pixels. Only an amateur engaging in a false conceit believes that "more is better", which is the case with you and your notion that "you can't have too much resolution" in a lens. Such a notion is untrue.



https://www.schneideroptics.com/pdfs/whitepapers/Megapixel_Lens.pdf

Theoretically, what's more important is the relationship between the MTF (read contrast cycle) and the sensor cycle. It's probable the 5MP lens nearer matches that ideal which is why there's a visible improvement. I can't say I'm an expert on the theory, you probably know more theoretically than me here. However, as you pointed out above, it's not always about the theory...

Again, more pretentious gibberish that reveals that you don't understand the concepts you are talking about. MTF is not a "contrast cycle". And "sensor cycle" is a bogus term.

It's time for you to get a grip and finally move on from your "M12 lens porn fantasy.

 

[c4rc4m]

The fact of the matter is that different lenses with different optical formulas perform differently. You can have two lenses with the same focal length and the same ƒ-number that provide different amounts of DOF. It has nothing to do with you imagained notion that, "that differences seen could be down to small differences in aperture especially at the cheaper end of the market". As with so many of the pronouncements you make about optics this is pure fanatsy.

DOF is directly related to aperture size (thus f stop). There may be other influences, but aperture is the greatest factor involved period.

Another pie in the sky fantasy that has nothing to do with M12 lenses, how they are manufactured or the markets for them.

As I've said many times before, you tend to rubbish anything that falls outside of your application. I'm fully aware the chances of fluorite ever appearing in a dashcam lens is near zero. It was part of a wider discussion on lens manufacturing costs (see above) not a realistic expectation. However, equally, to me quality is everything and I will take whatever any manufacturer chooses to make available at the top end. To me a dashcam is a dashcam, and an in car action camera and a potential B roll cam. If that falls outside of your usage fine. I don't have to justify mine, and nor does anyone else who wants better than ordinary dashcam performance because they want 1 camera for many in car uses. I'd rather spend double on a superb dashcam, than buy a dashcam and action cam, and it would probably be cheaper. Niche market yes. The top end always is.

SOME of US?! You are not willing to purchase a single aftermarket lens to experiment with, even one of the very worthy modest prices ones that many of have been working with. Some of us? Who are you kidding?

Willing or able? As explained previously, I don't have the money to spare throwing it around on lenses that might not work. I'll let those richer than myself play around and make the mistakes.

Again, you haven't a clue.

Again, more pretentious gibberish that reveals that you don't understand the concepts you are talking about. MTF is not a "contrast cycle". And "sensor cycle" is a bogus term.

It's time for you to get a grip and finally move on from your "M12 lens porn fantasy.

Again you know everything when you don't. Video is different to digital stills and yes you know a lot and yes I respect that and acknowledge in many areas of lens theory you know more. But as I said, CONTRAST is more important than exactly matching the nyquist resolution as it's the contrast that gives the sharpness with video. Hence where MTF comes into play:

A short paper on the part MTF and contrast plays: https://www.ien.eu/uploads/tx_etim/resolveopticsarticle2016a.pdf

Even a perfectly matched Nyquist resolution ratio will produce an unsharp video if the contrast ratio is low. It's a matter of balancing / matching both.

 

[Deleted member 37895]

For every lens the plane of what is perfectly in focus has zero thickness, it's literally a plane. However, a pixel is not infinitely small, so we consider something "in focus" if the resolution is exceeded by the sharpness of the image formed on the sensor (or film). So you can have an object behind or in front of the plane that still looks focused. For a given resolution, focal length, and aperture, depth of field is always the same. But a crappy lens that is blurry might have a depth of field that is indistinguishable from distances a little further and closer than that depth of field, just because nothing is really sharp

 

[Dashmellow]

DOF is directly related to aperture size (thus f stop). There may be other influences, but aperture is the greatest factor involved period.

Here we go again! You started this "discussion" by claiming that different lenses with the same aperture will exhibit the same amount of depth of field but that is simply not true. As always your comments are based on theory and speculation rather than actual hands on experience. As always, you ignore evidence and facts that are provided to you and continue to issue misinformation. When I described how I own two M12 4mm ƒ/1.2 lenses from different manufacturers that perform very differently optically and have different DOF capabilites despite both of these lenses having the same ƒ/1.2 aperture, you become conveniently deaf to these facts.

As I've said many times before, you tend to rubbish anything that falls outside of your application. I'm fully aware the chances of fluorite ever appearing in a dashcam lens is near zero. It was part of a wider discussion on lens manufacturing costs (see above) not a realistic expectation. However, equally, to me quality is everything and I will take whatever any manufacturer chooses to make available at the top end. To me a dashcam is a dashcam, and an in car action camera and a potential B roll cam. If that falls outside of your usage fine. I don't have to justify mine, and nor does anyone else who wants better than ordinary dashcam performance because they want 1 camera for many in car uses. I'd rather spend double on a superb dashcam, than buy a dashcam and action cam, and it would probably be cheaper. Niche market yes. The top end always is.

I'm not "rubbishing" anything! It's just that your continued referencing Super UD glass or fluorite for DSLRs that cost thousands of dollars each is simply an irrelevant and pretentious conceit that has no practical bearing on the use of M12 lenses in the class of cameras we are using. We will NEVER see fluorite lenses in dash cams because the price would be prohibitive and the optical payoff would be minimal.

Willing or able? As explained previously, I don't have the money to spare throwing it around on lenses that might not work. I'll let those richer than myself play around and make the mistakes.

My God! You make a remark like "Some of us are willing to pay for extra quality" but then turn around and say "I'll let those richer than myself play around and make the mistakes"? So, I guess, "some of us" doesn't include you. Well, who are you referring to exactly as the "some of us" since you are literally the only person here who compulsively advocates for the purchase of super high end lenses for dash cams. I feel embarrassed for you after reading such a disingenuous remark.

Again you know everything when you don't. Video is different to digital stills and yes you know a lot and yes I respect that and acknowledge in many areas of lens theory you know more. But as I said, CONTRAST is more important than exactly matching the nyquist resolution as it's the contrast that gives the sharpness with video. Hence where MTF comes into play:

A short paper on the part MTF and contrast plays: https://www.ien.eu/uploads/tx_etim/resolveopticsarticle2016a.pdf

Even a perfectly matched Nyquist resolution ratio will produce an unsharp video if the contrast ratio is low. It's a matter of balancing / matching both.

Oh Wow!! You looked up Optical transfer function and Nyquist frequency on the internet. How impressive! You know, your never ending sciolism is becoming downright nauseating at this point.

This business of MTF has NOTHING to do with the original statement you made about lens apertures always providing the same DOF regardless of which lens you're using. It's just another one of your characteristic distractions when you get called out on having your facts wrong.

Of course, when actual authoritative evidence was presented to you about the key relationships between sensor pixel size and lens resolution for each given sensor and the resulting image quality you simply ignore this too because it refutes your "more resolution is always better" wanker fantasy.

 

[c4rc4m]

Here we go again! You started this "discussion" by claiming that different lenses with the same aperture will exhibit the same amount of depth of field but that is simply not true. As always your comments are based on theory and speculation rather than actual hands on experience. As always, you ignore evidence and facts that are provided to you and continue to issue misinformation. When I described how I own two M12 4mm ƒ/1.2 lenses from different manufacturers that perform very differently optically and have different DOF capabilites despite both of these lenses having the same ƒ/1.2 aperture, you become conveniently deaf to these facts.

It's a basic of photography that DOF is related to aperture. Jackalaphoto offered one possible explanation above. I offered another possible explanation in the form of quality control. There may be others factors. However, DOF is directly related to aperture size.

I'm not "rubbishing" anything! It's just that your continued referencing Super UD glass or fluorite for DSLRs that cost thousands of dollars each is simply an irrelevant and pretentious conceit that has no practical bearing on the use of M12 lenses in the class of cameras we are using. We will NEVER see fluorite lenses in dash cams because the price would be prohibitive and the optical payoff would be minimal.

Yo're not reading properly. Above I was answering a question as to why quality lens manufacturing costs were still high given modern mass production techniques, a point raised by another member. Fluorite and it's manufacturing process was one example of that. Again, for the 3rd time, I don't realistically expect to see fluorite on any dashcam, although I wouldn't turn it down either.

My God! You make a remark like "Some of us are willing to pay for extra quality" but then turn around and say "I'll let those richer than myself play around and make the mistakes"? So, I guess, "some of us" doesn't include you. Well, who are you referring to exactly as the "some of us" since you are literally the only person here who compulsively advocates for the purchase of super high end lenses for dash cams. I feel embarrassed for you after reading such a disingenuous remark.

Not really. I can save for a quality dashcam. That's far different to having a pile of useless lenses which is money wasted, sat in a cupboard somewhere. 1 is money well spent, the other is money wasted.

Oh Wow!! You looked up Optical transfer function and Nyquist frequency on the internet. How impressive! You know, your never ending sciolism is becoming downright nauseating at this point.

This business of MTF has NOTHING to do with the original statement you made about lens apertures always providing the same DOF regardless of which lens you're using. It's just another one of your characteristic distractions when you get called out on having your facts wrong.

I never said it did. I said MTF directly affects the sharpness of the recorded image from the lens, and is more important than matching the Nylquist as in the link I posted: https://www.ien.eu/uploads/tx_etim/resolveopticsarticle2016a.pdf

 

[Dashmellow]

It's a basic of photography that DOF is related to aperture. Jackalaphoto offered one possible explanation above. I offered another possible explanation in the form of quality control. There may be others factors. However, DOF is directly related to aperture size.



Yo're not reading properly. Above I was answering a question as to why quality lens manufacturing costs were still high given modern mass production techniques, a point raised by another member. Fluorite and it's manufacturing process was one example of that. Again, for the 3rd time, I don't realistically expect to see fluorite on any dashcam, although I wouldn't turn it down either.



Not really. I can save for a quality dashcam. That's far different to having a pile of useless lenses which is money wasted, sat in a cupboard somewhere. 1 is money well spent, the other is money wasted.



I never said it did. I said MTF directly affects the sharpness of the recorded image from the lens, and is more important than matching the Nylquist as in the link I posted: https://www.ien.eu/uploads/tx_etim/resolveopticsarticle2016a.pdf

Good Lord!, so now you are stretching your logic to the point of blaming the difference between DOF performance between two disparate lenses (from different manufacturers) that are entirely unknown to you and which you have never seen, handled or tested on "quality control". Unbelievable! Obviously, you've run out of wacky logic to offer and despite the best evidence refuse to observe the laws of physics, optical design, the concepts of relative aperture vs effective aperture vs absolute aperture, entrance pupils, or any other known factors that have been pointed out to you.

Somehow you've suddenly miraculously shifted from compulsive table pounding about the virtues of ridiculously expensive high end, distortion free lenses that apparently according to you everyone here, except you, should run out and purchase now to "money wasted" on other interesting, viable and worthwhile lenses that you also refuse to purchase but that many of use have had a grand time experimenting with, learning about, benefiting from and putting into daily use with excellent results. Oh, that we could all be such ivory tower elitists like you looking down our noses at these "useless" lenses that we only know about because we've read about them on the internet.

You know, @c4rc4m, I've had just about enough of this. Not long ago, you accused me of "jumping in to attack you" and even libeling you. And you then went on to state that you want nothing to do with me on this forum, even claiming that you had "blocked" me. Yet since then you repeatedly mention me by name in your posts, tag me in posts or as you've done here in this thread and elsewhere quote some remark I've made with a reply that is guaranteed to elicit a reply from me. In this case, you made claims that had nothing whatsoever to do with what I said but that apparently were engineered to start one of these endless petty disputes which you then carry on for days.

You did the same thing last August when I casually mentioned that I might like to experiment with some IR flash photography, "jumping in" and insisting that it won't work despite the fact that I never said what I intended to do or what type of still or video camera I intended to do it with. Yet for some reason you continued relentlesly pressing the issue, day after day presenting incorrect information that you found on the internet, and having no personal experience with IR photography until you had provoked a fight. Like now, you go on with this crap for as long as you can keep it going in what is beginning to amount to some weird form of trolling.

You need to stop this behavior.

You are entitled to say what ever you like here on this forum however vicarious, incorrect, ignorant or pie in the sky your observations and opinions may be, but please leave me out of it. Like I've said, I've had just about enough of your sciolist, prentious and provocative attitude.

 

[c4rc4m]

Good Lord!, so now you are stretching your logic to the point of blaming the difference between DOF performance between two disparate lenses (from different manufacturers) that are entirely unknown to you and which you have never seen, handled or tested on "quality control". Unbelievable!

I said it could be one possible explanation. Jakalphoto added another. For someone who claims to be the photographic guru of this forum, you seem not to know the basics of photography that DOF is largely the result of aperture. It's in every photography book you care to read. Every professional photographer will tell you the same. Yes perhaps there may be some other more minor influences, of which myself and Jackalaphoto mentioned 2 possible explanations for the differing results from 2 otherwise identical lenses, but the primary factor is still aperture (assuming both lenses are adjusted focally for max DOF).

You know, I've had just about enough of this. Not long ago, you accused me of "jumping in to attack you" and even libeling you. And you then went on to state that you want nothing to do with me on this forum, even claiming that you had "blocked" me.

You may have libelled me, which is why Admin removed your post and sent you a warning.

Your general paranoia is unbelievable. I've just joined in discussions. The whole I'm hunting you down theory is beyond belief. I rarely if ever criticise you except in response to an attack on myself, and even then I remain polite. I've lost count of the number of times I've actually liked your posts, even recently.

You did the same thing last August when I casually mentioned that I might like to experiment with some IR flash photography, "jumping in" and insisting that it won't work despite the fact that I never said what I intended to do or what type of still or video camera I intended to do it with.

Ah, so now I understand. Anyone who engages you in a discussion that questions whether something you have suggested might be workable is attacking you. You really are paranoid. Forums are for discussion where people suggest ideas and others give views as to whether they will work or can bet bettered etc. The whole idea that quite frankly, you make a suggestion and no-one can discuss the merits of it is both absurd and goes against what a forum is about.

I've had just about enough of your sciolist, prentious and provocative attitude.

So I'm a Socialist because I'm not rich, and pretentious and provocative because I use a forum for what it's intended for, to discuss ideas and their merits. Like I said paranoid, and btw on the subject of politics, most of the EU is comprised of Socialist countries that would find that comment offensive, although I wouldn't necessarily describe myself as Socialist.