Big Lenses for the Mobius MAXI

[Rocketvapor]

Just started with my first Mobius and after some Computer and Windows issues got access to parameters with mSetup (5.0.1.1) and
Web Cam mode using CyberLink YouCam. Occasionally I can lock up the camera by playing with YouCam setting.
Or, if I try to enable Windows Camera.
I'll try and post enough details and pictures so others can try various lenses. There are probably better ways of going about this but I'm using mostly what I have lying around.
I have a couple 2.8-12mm, F1.2, and the 'Longest' M12 I have is a 25mm, in C mount 7.5-50mm, f1.4 but 50mm ain't enough
So, I play with old 35mm lenses, and some 6X7 (just for shock value ).
Sorry, I don't have any f1.2 apertures in my with long focal length lenses.
A lot of this will follow what I did with my G1W dashcam in another thread. The G1W is convenient because of the display, but the MAXI is more of a 'camera'.


I started with a C to M12 adapter and put a 13mm IR cut filter in the front with a couple dabs of epoxy.
Assembled and could not get to infinity focus. The back focus works well with other M12 cameras so I trimmed the nose of the MAXI case (Shhhhh).
Seems the lens holder is coated on the inside (anodize?) and threading the adapter dropped specs onto the sensor.
Took the holder off and directly cleaned the sensor, over and over. Finally think I have it clean.

So far I've tried a few Pentax K mount lenses-a 28-80mm and a 28-300, and a Pentax 6X7 165mm. During daylight (cloudy) the MAXI handles stopping down well,
f8 gives a good depth of field and sharpness.
I post pictures soon and maybe a couple of videos.

 

[Rocketvapor]

A couple build pics. First the 13mm IR Filter.

Then with the P/K adapter

and then with a 6X7 165mm lens with a tripod mount and a monitor

Next, my long range lens testing facility. A street sign 480 yards away.
I use it for comparing lens resolution.

This is a photo taken with the MAXI and a cropped insert.


During the day the heat causes a lot of mirage over the distance.
I use the signs to test most of my long telephoto lenses
Previous Examples

 

[Rocketvapor]

Here's a short video (new at this) showing my first lens test.
Maybe this will work.
30 sec video

Another video, using these settings

Uploaded in lower resolution. In the first segment you can really be the effects of heat mirage at longer ranges.
Maxi test 2

Last segment used the 165 lens and a X2 teleconverter.


And a 3rd Video.
Test 3, 100-500mm
Shot in 1080, uploaded in 720.

A 100-500mm lens, Pentax mount.

 

[Rocketvapor]

and just in case,
more pictures

 

[Dashmellow]

How do you determine the correct flange focal distance when you install the lens adapter on the Mobius module?

 

[Rocketvapor]

The 35mm to C mount adapter is pretty standard.
The PK, Nikon, and Canon that I have are set for the back focus for the respective 35mm film camera.

When adding the M12 to C adapter (a CS adapter would probably need a 5mm extension) to the 35mm adapter (and the 6X7 ) I adjust for a little bit more than infinity focus.
The Mobius Maxi case extended out past the lens holder, which seemed to be about right after I trimmed the plastic case back.
It also looked like they had to dremel the inside a little for the lens holder to fit.
If I was just going to do Macro the case would have been fine, just wouldn't make infinity.

This PK to C adapter has 3 grub screws to rotate the C threads. I might have to modify it so I can attach a tripod mount. The 6X7 adapter has one but not the 35mm adapter and I can't have all that weight hanging off the Mobius, and hand holding is pretty much out of the question

With Dashcams and Action cams the back focus does not seem to be standard (large thread adjustment range) and is a little hit and miss.

I also might need to 360 seal the IR filter. I suspect the air pumped with a push-pull zoom moves air in and out of the lens holder (it is not sealed around the sensor).
Dust spots really show up on this sensor. Seems worse than my DSLRs.

 

[Rocketvapor]

Tried motion detect but so far haven't mastered it.
Might try it on the bird house and see if it will detect the birds coming and going.
\
So far, I'm impressed with the image quality (better than the G1W) and am getting better at hooking it up and changing settings.

 

[Dashmellow]

The 35mm to C mount adapter is pretty standard.
The PK, Nikon, and Canon that I have are set for the back focus for the respective 35mm film camera.

When adding the M12 to C adapter (a CS adapter would probably need a 5mm extension) to the 35mm adapter (and the 6X7 ) I adjust for a little bit more than infinity focus.
The Mobius Maxi case extended out past the lens holder, which seemed to be about right after I trimmed the plastic case back.
It also looked like they had to dremel the inside a little for the lens holder to fit.
If I was just going to do Macro the case would have been fine, just wouldn't make infinity.
View attachment 38770
This PK to C adapter has 3 grub screws to rotate the C threads. I might have to modify it so I can attach a tripod mount. The 6X7 adapter has one but not the 35mm adapter and I can't have all that weight hanging off the Mobius, and hand holding is pretty much out of the question

With Dashcams and Action cams the back focus does not seem to be standard (large thread adjustment range) and is a little hit and miss.

I also might need to 360 seal the IR filter. I suspect the air pumped with a push-pull zoom moves air in and out of the lens holder (it is not sealed around the sensor).
Dust spots really show up on this sensor. Seems worse than my DSLRs.

Thanks for the info! I'm still a little uncertain how to make this work. I'll explain.

I have mostly Nikon F mount lenses these days (sold off my Mamiya 6x7 system a couple of years ago along with several pricey view camera lenses)

The last time I looked into doing something like this with the Mobius I look at several resources on the internet to understand how to accommodate for the flange focal distance of my Nikon lenses. As you obviously know, each brand of lens uses a different flange distance. For Nikon F mount, the distance between the flange and the sensor is 46.50 mm. According to Wikipedia, the flange focus distance "usually measured in hundredths of millimeters". I figure there's probably some wiggle room depending on the focal length and that also sounds a bit like what you are doing when you mention "adjust for a little bit more than infinity focus".

So, at this point I can see how this needs to work but with the Nikon F to C mount adapter and the C mount to M12 adapter, what is the best technique to get the whole thing to come together? How do you make the adjustments. I figure it might involve trimming back the M12 lens barrel module a millimeter at a time until you get the Nikon lens to focus on the Mobius sensor plate or something like that.

 

[Rocketvapor]

The registration distance for the Nikon to C adapter should be accurate. I have one in use with a 28-200 Nikon lens and a C mount CCD security camera.
The flange on the C to M12 adapter has contacted almost every M mount camera I have necessitating trimming the sensor housing.
The Mobius Maxi case extended out past the sensor /lens housing. Trimming the case back close gave me enough to seat the adapter flange.
Small M12 lenses do not interfere with the Maxi plastic case the adapter flange does.
Don't know about the other Mobius models.

I would get a $15 dollar Nikon to C and a $6 C to M12 and give it a go
A whole millimeter is a lot, especially with a 1/3" sensor, maybe a fraction of that at a time.
Didn't take a pic of the Maxi case before I trimmed it but you can see it is about flush with the sensor/lens housing.




I want to do the same thing with my SJCAM M20 but the case really shrouds the lens holder.
Might have to make a special adapter using a shorter adapter, like PK to 4/3 , a homemade adapter with a longer M12 thread to reach way inside the case.

 

[Dashmellow]

The registration distance for the Nikon to C adapter should be accurate. I have one in use with a 28-200 Nikon lens and a C mount CCD security camera.
The flange on the C to M12 adapter has contacted almost every M mount camera I have necessitating trimming the sensor housing.
The Mobius Maxi case extended out past the sensor /lens housing. Trimming the case back close gave me enough to seat the adapter flange.
Small M12 lenses do not interfere with the Maxi plastic case the adapter flange does.
Don't know about the other Mobius models.

I would get a $15 dollar Nikon to C and a $6 C to M12 and give it a go
A whole millimeter is a lot, especially with a 1/3" sensor, maybe a fraction of that at a time.View attachment 38791

Thanks! That explains it and basically confirms my thinking. I guess the C mount to M12 mount is why I had the the questions. I thought it might require several millimeters to be trimmed, so I'm please to hear it is likely less than that.

Yeah, the thing with M12 lens is that they don't have a flange. (except the varifocals, if screwed all the way in as they are designed)

 

[Rocketvapor]

Once you get one of your dashcams modified to a Nikon mount, then the fun begins
28-200 for tele, and
reversing ring and extension rings for some cheap macro.

 

[Rocketvapor]

Here's a quick attempt at Macro with the Maxi.
28-200mm Nikon, reversed.



This is fun
A contact on a Micro SD card. Take one out and look at it.

 

[Rocketvapor]

One more and I'll stop chewing up bandwidth
A crop from a white zone on my Samsung S8 display

You think depth of field is a problem? Try MacroPhotography

Once I got each shot set up I set Time Lapse (photo mode) for 3 seconds and let it run as I fine focused.
Going through menu selections on the A/V display was interesting.
Since space is limited in the KLAS (Kitchen, Lab, Armory, Shop) I used one of those really cheap 3.5" monitors to watch the A/V output while recording the pics.

 

[Rocketvapor]

I've been playing a little more with some Macro techniques, Lens Tilt and Swing.
I made up a tilt adapter from an extension tube set (Pentax K mount) and put a foam shim with a hole cut out, some little 90deg brackets, hose clamps, and machine screws. Anyway, took some shots with a DSLR to see it I could adjust for a Focal Plane that would give me a larger apparent Depth Of Field.
Doesn't really increase DOF, just moves the Focal Plane closer to Horizontal.
Man that hurts just to thing about it
Tomorrow I'll put the tilt adapter and try it on the Maxi. Seems to work with the DSLR.
Here's the contraption on the K-r


And a comparison of without tilt, and with tilt. Now maybe I can get my bug pictures into better focus from front to back.


Seems like a little tilt would be a help with normal Dash Cam usage also. I''m going to order a few of the plastic lens holders (18mm spacing) from China and shave the bottom of the holder to give a few degrees of downward tilt to the lens. 4 or 5 degrees of tilt and the screws should still hold in it place. The goal being to bring objects closer and farther away into better focus.
The lens would need to have a larger image circle to prevent vignetting. Something for a slightly larger sensor than the Mobius should work.
Anyway, too late tonight to set up the Maxi and see how it does.
*correcting errors, typing in the dark

 

[Rocketvapor]

Here's what the Tilt/Swing Contraption looks like. I can add in more extension spacers for longer lenses. Scrunching the screws compresses the foam but adjustment is limited.

 

[Rocketvapor]

Looks like it will be close to a month before my Chinese lens holders come in
I'm gonna also order some for a cheap dash cam I have to experiment with.
I'm guessing than tilt, used for scenic photography, will also work for DashCams.
This poor sketch is a really rough guess on how this will change the Plane of Focus looking down the road.
Any pro photographers have an opinion if this will be a benefit??

 

[Dashmellow]

Here's what the Tilt/Swing Contraption looks like. I can add in more extension spacers for longer lenses. Scrunching the screws compresses the foam but adjustment is limited.
View attachment 39157

That looks cool! You've basically created a kind of home made Lensbaby.

 

[Dashmellow]

Looks like it will be close to a month before my Chinese lens holders come in
I'm gonna also order some for a cheap dash cam I have to experiment with.
I'm guessing than tilt, used for scenic photography, will also work for DashCams.
This poor sketch is a really rough guess on how this will change the Plane of Focus looking down the road.
Any pro photographers have an opinion if this will be a benefit??View attachment 39178

At one time I did a lot of architectural photography using 4x5 view cameras and tilt/shift PC (Perspective Control) lenses on 35mm and 6x7 format (Mamiya RZ). I don't see why using the same techniques wouldn't work on the Maxi or other similar cameras but my hunch is that using these big lenses on such tiny sensors might exaggerate tilt angles to the point where fine adjustments could be tricky to control. I guess you'll have to see what happens. The interesting part of what you are doing here is that 35mm format camera lenses will throw an enormous circle of coverage on the 1/3" sensor that will provide plenty of room for tilt/shift adjustments. (Conceivably you could add a shift function to your project if you wanted to.)

The DSLR lenses I used look similar to this which is of course, what you are sort of recreating with your "Contraption". Seems like a fun, interesting project.

 

[Rocketvapor]

Mine is MUCH Cheaper
The 35mm format works well with a APS-C DSLR. I'm guessing a lens for a 1/2.5" would allow some tilt with a 1/3" sensor.

I just took some more pics with the Maxi. Watched on the video monitor as I let the camera snap pictures.
Adjusted until it looked pretty good on the monitor. Then pulled the SD card and NOT so good.
I'll try (some time in the future) to capture some frames from the A/V out and compare them to SD captured images.
I have max quality and max photo resolution set but the saved images do not appear as sharp and have a problem with bright edges.
The compression algorithm might need some work.
Or, it could just be me
The original image was 2704x1624, I reduced it to 1280x720 to post here.

Do you think the varizoom you have would cast a proper circle on the Mobius sensor with about 3 degrees tilt?
Tilt and shift would be much harder to implement. Tilt would just be a shave of the lens holder.

I might try the Maxi on a video microscope that presently has a 640x480 camera.


Went outside with a 105mm 6x7 lens and the extra light caused some loss of contrast. I have to open the Contraption up and blacken the surfaces I had to machine.
I wonder if a field stop would help?

 

[Dashmellow]

Do you think the varizoom you have would cast a proper circle on the Mobius sensor with about 3 degrees tilt?

That's an interesting question. When I get some time I will see if I can come up with an answer. In fact, it seems to me that if it works it would be possible to build a miniature M12 sized version of your "Contraption".