DSLR vs iPhone

[david_b]

I'm looking at the results from my Canon EOS 5D MkII full frame camera attached to the trinocular tube a Motic BA310 using Motic photo tube & photo eyepiece and seeing more than expected Chromatic aberration in the form of yellow fringeing towards the edge of the frame. The first image is a screenshot of part of an image opened in Photoshop at 100% (no sharpening or other editing). I do not see this yellow fringeing when looking through the eyepiece of the microscope.
The second image is taken using my iPhone attached to the eyepiece of the same microscope using a phone adapter, which shows no yellow fringeing.
I'm disappointed with the result of the DSLR and unsure if the problem is the camera or the photo tube optics.
Has anyone else made a similar comparison between phone and DSLR?

https://ibb.co/RPHNWFP
https://ibb.co/pQpRMsZ

[MichaelG.]

Ouch ... that’s very disappointing, David

First thought is that the photo eyepiece must be ‘correcting’ for chromatic aberration that wasn’t there in the first place !
... if you see what I mean.

MichaelG.

.

Edit: I’ve just checked the Motic site, and confirmed that your ‘scope is ‘CCIS’
.. is the photo adapter the one specified for it ? or is it a K version ?

[75RR]

If you have a tripod you can take a test 'Afocal' shot through either one of the binocular eyepieces or place an eyepiece in the photo-tube and try there.

That should eliminate the camera as suspect at least.

[david_b]

Ouch ... that’s very disappointing, David

First thought is that the photo eyepiece must be ‘correcting’ for chromatic aberration that wasn’t there in the first place !
... if you see what I mean.

MichaelG.

.

Edit: I’ve just checked the Motic site, and confirmed that your ‘scope is ‘CCIS’
.. is the photo adapter the one specified for it ? or is it a K version ?

I'm not sure what a 'K' version is but the photo tube and eyepiece were supplied with the microscope by a Motic dealer.
It looks like a generic Chinese optic...

[MichaelG.]

https://moticeurope.com/en/25x-photo-ey ... apter.html

... looks the same

I admit to being a little bewildered

MichaelG.

[75RR]

That does seem to be the recommended option.

The catalogue numbers match up but the prices don't:

https://moticmicroscopes.com/collection ... 1000300442

https://moticeurope.com/en/25x-photo-ey ... apter.html

[MichaelG.]

https://moticeurope.com/en/25x-photo-ey ... apter.html

... looks the same

I admit to being a little bewildered
.
.

I'm not sure what a 'K' version is but the photo tube and eyepiece were supplied with the microscope by a Motic dealer.
It looks like a generic Chinese optic...

MichaelG.

.
K is just the usual shorthand for ‘compensating’
...

[david_b]

To remove any confusion from the sample slide, I repeated the test using a calibration slide.
The iPhone XS (second image) is much as expected from a phone sensor, but the Canon DSLR (first image) is truly awful...

[75RR]

If you don't want to try 'Afocal' you can as an alternative place one of your eyepieces in the phototube, you will need to raise it some 5mm with a spacer, that will effectively turn it into a projection eyepiece.

[david_b]

Here's an afocal image from the DSLR through the eyepiece using a 50mm lens... better but still not great. These are raw images so no sharpening...

[apochronaut]

Firstly, your trinocular tube image is not only mal-corrected it is mis-aligned. The axis is shifted towards 4 o'clock.
This is definitely an optical mis-match. The photo tube should provide a nicely corrected image to your awaiting sensor. Case closed. You refer to a "dealer". They obviously made a mistake or they are incompetent. I have in the past encountered a long standing Motic dealer who did not know what N.A. meant. In his case, I was suspicious of just what he was a dealer of!

[Scarodactyl]

Dslr adapters are often an afterthought at best on these systems. A dslr is not going to introduce its own abberations so you can eliminate thr camera itself--I think michaelg is right that the photo eyepiece is mismatched. My impression was that Motic infinity options did not use compensating eyepieces (and are generally based on Olympus's infinity objectives, spec-wise).

[Zuul]

Firstly, your trinocular tube image is not only mal-corrected it is mis-aligned. The axis is shifted towards 4 o'clock.
This is definitely an optical mis-match. The photo tube should provide a nicely corrected image to your awaiting sensor. Case closed. You refer to a "dealer". They obviously made a mistake or they are incompetent. I have in the past encountered a long standing Motic dealer who did not know what N.A. meant. In his case, I was suspicious of just what he was a dealer of!

Could you point out the artifacts that lead to this conclusion and the corrections required to the system to fix it? I think that would be very helpful to others having similar troubles.

[david_b]

Firstly, your trinocular tube image is not only mal-corrected it is mis-aligned. The axis is shifted towards 4 o'clock.
This is definitely an optical mis-match. The photo tube should provide a nicely corrected image to your awaiting sensor. Case closed. You refer to a "dealer". They obviously made a mistake or they are incompetent. I have in the past encountered a long standing Motic dealer who did not know what N.A. meant. In his case, I was suspicious of just what he was a dealer of!

If you mean that the lines in the calibration slide do not run exactly north/south, this can be adjusted by slightly loosening the tube's screw fitting; overtightening the two halves of the tube causes the misalignment. Tolerences are obviously not great but I can live with this.
What I can't live with is the image quality and I'm unsure if this is a faulty optic, if I have an incorrect eyepiece, or if this is just typical of the Motic offering.

[Hobbyst46]

In fact, when the iphone image of the stage micrometer is enlarged, considerable CA is visible edge to edge including the center, again supporting that the camera itself is not the source of the problem.

[Zuul]

Firstly, your trinocular tube image is not only mal-corrected it is mis-aligned. The axis is shifted towards 4 o'clock.
This is definitely an optical mis-match. The photo tube should provide a nicely corrected image to your awaiting sensor. Case closed. You refer to a "dealer". They obviously made a mistake or they are incompetent. I have in the past encountered a long standing Motic dealer who did not know what N.A. meant. In his case, I was suspicious of just what he was a dealer of!

If you mean that the lines in the calibration slide do not run exactly north/south, this can be adjusted by slightly loosening the tube's screw fitting; overtightening the two halves of the tube causes the misalignment. Tolerences are obviously not great but I can live with this.
What I can't live with is the image quality and I'm unsure if this is a faulty optic, if I have an incorrect eyepiece, or if this is just typical of the Motic offering.

I suspect Apochronaut means that your camera’s sensor is not parallel to the stage.

[david_b]

In fact, when the iphone image of the stage micrometer is enlarged, considerable CA is visible edge to edge including the center, again supporting that the camera itself is not the source of the problem.

I seemed reasonable to me for a small phone sensor but perhaps I'm easily pleased!
Do you have a similar test image from a smartphone we could compare?

[mrsonchus]

As above I suspect, Apo' has the nub of it...
I'd pursue this if I were you.

[Hobbyst46]

In fact, when the iphone image of the stage micrometer is enlarged, considerable CA is visible edge to edge including the center, again supporting that the camera itself is not the source of the problem.

I seemed reasonable to me for a small phone sensor but perhaps I'm easily pleased!
Do you have a similar test image from a smartphone we could compare?

Regretfully no. When I used the phone camera, years ago, I did not have a stage micrometer. Later, I abandoned cellphone photomicrography in favor of a mirrorless camera and an eyepiece camera, and my comment was based on experience with such cameras.