Imaging with a DSLR

Here you can discuss different microscopic techniques and illumination methods, such as Brightfield, Darkfield, Phase Contrast, DIC, Oblique illumination, etc.
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MikeBradley
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Joined: Sat Sep 22, 2018 4:29 pm
Location: Sunshine Coast, BC, Canada

Imaging with a DSLR

#1 Post by MikeBradley » Thu Nov 29, 2018 7:21 am

I’m wondering how other DSLR users set their cameras for micro-photography. I’m using a Canon 60Da with a relay lens adapter (so called “2x” but actually much higher) on the trinoc. tube of an Olympus BH2 at 4-40x objective. I think that my images are quite good but they could be better, especially when imaging low colour/low contrast objects in brightfield. I usually use the free Canon EOS Utility but sometime I use an astro-imaging program – BYEOS for its greater flexibility. My questions for the group are:

a) What camera setting are people finding most useful for microscope use, Tv, Av, P, B, M etc? Is this question even answerable?
b) Does the “Silent Shooting” mode offered on some cameras really help avoid camera shake?
c) How do DSLR users adjust the white balance when microscope imaging? For every shot?
d) Do DSLR users use a blue filter in the light path to achieve colour balance?
e) Astro-imaging has shown me that my camera is least noisy at 1600 ISO, why wouldn't that be my default speed/gain?

Thanks
Michael
Olympus BH2,
AO110
Carl Zeiss Standard WL
Canon 60Da

MicroBob
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Joined: Sun Dec 25, 2016 9:11 am

Re: Imaging with a DSLR

#2 Post by MicroBob » Thu Nov 29, 2018 12:40 pm

Hi Michael,

a) The aperture should stay wide open or nearly wide open. So A for aperture priority or M are useful modes. The cameras light meter trys to acheive something like an 18% grey grade. For micro images this often doesn't fir so exposure compensation is needed.

b)Electronic first shutter curtain is very important for top class images. Many Canon DSLRs offer it, I don't know whether you camera does. Most other DSLRs close and open the shutter when releasing from live view. This really leads to blurred images, for me unexpected but proven.

c) I use either auto white balance or raw format

d) I use mainly LED lighting but would suggest to use the blue filter. The spectrum then fits better to the sensor. The blue filter also protects the eyes from too much IR.

e) I'm quite sure that this is not right. You should get the best quality around base ISO. Unless you need short exposure times this will be the best choice.


Bob

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75RR
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Re: Imaging with a DSLR

#3 Post by 75RR » Thu Nov 29, 2018 1:54 pm

c) How do DSLR users adjust the white balance when microscope imaging? For every shot?
Best to set the white balance with every change in subject/lighting/objective.
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)

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Aenima
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Re: Imaging with a DSLR

#4 Post by Aenima » Thu Nov 29, 2018 3:54 pm

yeah ISO 800-1600 is good for astro, (long exposures and pixel integration/stacking) but for most other types of photography these ISO values are quite high - i would aim to use 100 - 200 ISO unless very fast shutter speeds are needed, say for moving subjects (pond-critters etc) - but even then its better to try to slow the critters down with other means (like coverslip pressure) rather than use high ISO.

HTH

On the DSLRs that i've used (an EOS 1000D and EOS1200D) silent-shutter/live view does provide reduction in vibration. You can test whether your camera has it by setting a long exposure time of around 2-3sec while using live view - then you can actually hear a slight 'swish' when triggered, followed by the 2-3sec exposure and lastly the clunk-click of the mirror. So the swish would be the EFCS (silent shutter) in effect, with the mirror only being used after the exposure. Give it a try. :)

P.s some models have silent shutter as automatic in live view, some models you need to select it. From what i've read its the cheaper models that use it as automatic during LV. The 60da i'm unfamiliar with so you'd have to test it out.

Might be worth using custom WB if you are finding it difficult to get right. A quick shot of the (out of focus?) light source without anything (on the slide) getting in the way should get you a usable CWB image for the camera to use. Maybe add a few additional tweaks to the WB towards the blue end to dial it in a bit more? It seems to vary quite a bit with microscopes so 75RRs suggestion of re-doing it is likely best, so a CWB could make sense there.


Not sure if any of this will help, but posting just in case - also i'm still learning the ins and outs myself and understand the need for lots of questions :)

good luck with it :)

MikeBradley
Posts: 76
Joined: Sat Sep 22, 2018 4:29 pm
Location: Sunshine Coast, BC, Canada

Re: Imaging with a DSLR

#5 Post by MikeBradley » Sat Dec 01, 2018 5:46 pm

Thanks for the various suggestions and answers to my questions Aenima, 75RR and MicroBob, it was all very helpful. I'll now try making the changes you suggested, wish me luck!
Michael
Olympus BH2,
AO110
Carl Zeiss Standard WL
Canon 60Da

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