Light "bloom" in middle of image?

[Brutha]

Hi All,

I thought I'd have a go at taking some images with my new Swift 380T and Canon 550d DSLR.

For connecting the camera to the trinocular port, I am using an adapter I have for astronomy, which fits into a 2x Barlow, then I've 3d printed an adapter that fits over the port and receives the camera with Barlow. It focuses pretty well BUT I am getting a white "bloom" in the middle of the image - see attached.

Any suggestions for possible fixes?

Thanks!

Brutha

IMG_8622.jpg (137.12 KiB) Viewed 5742 times

[patta]

Three guesses:

1. it is the reflection sensor-barlow-sensor.
Patch: change a bit the distance sensor-barlow & hope it gets better. If the barlow was working on the telescope, than no, should something else.

2. shine/reflections from the adapters (most probable)
Patch: paint black or floc the adapters.... or easier, cut a baffle (disk with hole) out of cardboard and glue it on the bottom of the adapter
with aperture hole as small as possible, until vignettes; like 10mm or 3/8".
Always design baffles in the next 3D printed adapters! Or a sawtooth profile for the inner surface.

3. parfocal distance is way off, reflections comes from the objective that is working at wrong distance.
patch: check if the camera is in focus when also is in focus at the eyepiece. adjust adapters distance so it is such. Especially Plan or LWD objectives do this issue.

may be more?
I've never tried a telescope barlow on the microscope. That is very interesting as is similar to the "Homal" photo eyepieces, may improve the image quality.
Can you post a photo of your stack?

[patta]

Guess 4:
England-Italia. 1-3
it isn'nt off topic, nonono, I 'll see the match at the eyepiece with phone-confocal-live

[Brutha]

Three guesses:

1. it is the reflection sensor-barlow-sensor.
Patch: change a bit the distance sensor-barlow & hope it gets better. If the barlow was working on the telescope, than no, should something else.

2. shine/reflections from the adapters (most probable)
Patch: paint black or floc the adapters.... or easier, cut a baffle (disk with hole) out of cardboard and glue it on the bottom of the adapter
with aperture hole as small as possible, until vignettes; like 10mm or 3/8".
Always design baffles in the next 3D printed adapters! Or a sawtooth profile for the inner surface.

3. parfocal distance is way off, reflections comes from the objective that is working at wrong distance.
patch: check if the camera is in focus when also is in focus at the eyepiece. adjust adapters distance so it is such. Especially Plan or LWD objectives do this issue.

may be more?
I've never tried a telescope barlow on the microscope. That is very interesting as is similar to the "Homal" photo eyepieces, may improve the image quality.
Can you post a photo of your stack?

Ah, thanks, some good stuff to investigate there! Yes, will post a photo, probably tomorrow after the game etc

[Brutha]

Guess 4:
England-Italia. 1-3
it isn'nt off topic, nonono, I 'll see the match at the eyepiece with phone-confocal-live

Hehe, there is 1 goal for England, just 3 more needed by Italia

But actually wouldn’t surprise me….

[patta]

Option 4. excluded by random

[Greg Howald]

You are using an unusual stack with the possibility of unusual intrusion of light. The image of reflection looks absolutely vertical. Try the most simple solution first. Block off the eyepieces so light can't enter the scope from that point.

[Brutha]

You are using an unusual stack with the possibility of unusual intrusion of light. The image of reflection looks absolutely vertical. Try the most simple solution first. Block off the eyepieces so light can't enter the scope from that point.

Thanks Greg, that’s a good thought - will give it a crack!

[patta]

thread on similar issue
https://www.microbehunter.com/microscop ... eb6d0b47bb

[Brutha]

thread on similar issue
https://www.microbehunter.com/microscop ... eb6d0b47bb

Ah, thanks Patta! It prompted me look at the interior of the Barlow which is aluminium, although not smooth, but rather threaded. I reckon flocking it somehow might be a good thing to try!

[Brutha]

2..... or easier, cut a baffle (disk with hole) out of cardboard and glue it on the bottom of the adapter
with aperture hole as small as possible, until vignettes; like 10mm or 3/8".

Aha! So, I 3d printed a little baffle to go in the Barlow lens, between the camera telescope adapter and the barlow optics. That seems to have fixed the problem! I suspect the pics will never be publication quality, but I'm happy with them!

I will post some example pics and a pic of the stack when I get moment (hopefully tomorrow if work stop being tiresome and insisting I do stuff for them when they're paying me )

Thanks a lot for that!

Cheers

Brutha

[Brutha]

I've never tried a telescope barlow on the microscope. That is very interesting as is similar to the "Homal" photo eyepieces, may improve the image quality.
Can you post a photo of your stack?

Ok, got some time today in the end! Here is a pic of the stack. It consists of:

• Canon 550d
• A telescope T mount / M42 adapter - something like this I guess, I bought mine some years back: https://www.amazon.co.uk/Elerose-1-25in ... 07JNSHWX7/
• A 2x Barlow ( I guess this one, it came with a Skywatcher telescope I bought years ago: https://www.amazon.co.uk/Watcher-1-25-D ... 00AVDWN9M/)
• Inside the Barlow I put a 3d printed baffle as you suggested, it's nicely trapped between the end of the t-mount and a little notch a bit above the Barlow optics.
• A 3d printed adapter that slides over the trinocular port, and holds the Barlow lens around 6mm from the top of the port.

Stack.jpg (150.69 KiB) Viewed 5461 times

I'm actually pretty happy with the results so far! Still a lot of playing around, but some examples below, marine samples from nearby. The shrimp thing is using the 4x objective the others the 10x. All done with stacking in Helicon Focus and a bit of tarting up in Lightroom (crop, sharpness, levels etc).

Now to figure out which software to use for capturing. Helicon remote is nice (since it has focus peaking), but unfortunately seems to have an issue recording video with the 550d. EOS utility has the video recording working, but no focus peaking! I am a bit limited being on Mac.

Cheers

Brutha

Thinga3.jpg (282.63 KiB) Viewed 5461 times

Thinga2.jpg (254.23 KiB) Viewed 5461 times

Thinga1.jpg (252.48 KiB) Viewed 5461 times

[DonSchaeffer]

Do you have any bright lights over you desk that might shine on your slide? I have had some issues with a large desk lamp.

[Javier]

I've never tried a telescope barlow on the microscope. That is very interesting as is similar to the "Homal" photo eyepieces, may improve the image quality.
Can you post a photo of your stack?

Ok, got some time today in the end! Here is a pic of the stack. It consists of:

• Canon 550d
• A telescope T mount / M42 adapter - something like this I guess, I bought mine some years back: https://www.amazon.co.uk/Elerose-1-25in ... 07JNSHWX7/
• A 2x Barlow ( I guess this one, it came with a Skywatcher telescope I bought years ago: https://www.amazon.co.uk/Watcher-1-25-D ... 00AVDWN9M/)
• Inside the Barlow I put a 3d printed baffle as you suggested, it's nicely trapped between the end of the t-mount and a little notch a bit above the Barlow optics.
• A 3d printed adapter that slides over the trinocular port, and holds the Barlow lens around 6mm from the top of the port.

Stack.jpg

I'm actually pretty happy with the results so far! Still a lot of playing around, but some examples below, marine samples from nearby. The shrimp thing is using the 4x objective the others the 10x. All done with stacking in Helicon Focus and a bit of tarting up in Lightroom (crop, sharpness, levels etc).

Now to figure out which software to use for capturing. Helicon remote is nice (since it has focus peaking), but unfortunately seems to have an issue recording video with the 550d. EOS utility has the video recording working, but no focus peaking! I am a bit limited being on Mac.

Cheers

Brutha

Thinga3.jpg
Thinga2.jpg
Thinga1.jpg

Very cool images!

[Brutha]

Do you have any bright lights over you desk that might shine on your slide? I have had some issues with a large desk lamp.

Hi Don,

Thanks! Actually I wondered about that a little since there were some bright lights - BUT once I put the baffle in the Barlow, it seemed to fix the problem, so it seems pretty clear the reflective inner surface of the Barlow was the problem.

Thanks,

Brutha

[DonSchaeffer]

Glad it worked out.

[patta]

Glad too it worked, images are nice
I'll give a try to the barlow lens.