Camera Focusing Challenges

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KitKestrel
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Joined: Tue Feb 02, 2021 4:43 am

Camera Focusing Challenges

#1 Post by KitKestrel » Thu Oct 21, 2021 3:05 pm

Hi all, again I come hat in hand hoping for some help :)

My setup is the 6D mk2 on a trinocular stereo microscope, so the camera lens is the adapter attaching the camera to the microscope. The camera is attached to a Windows laptop via a data cable and the laptop is running dpp4 with the associated EOS utility using Remote Shooting and Live View. When everything is working correctly, I bring the image of the target (say, watermeal) into the Live View window, touch the part of the image I want to focus on (the laptop has a touchscreen), press the remote shutter release button half way and the camera focuses, and then I complete the shot by pressing the shutter release button all the way. The lighting may not always be spot on, but the focus is.

Now for the problem. The press-the-button-halfway focus function has stopped working, and there is no halfway point - the button either takes the shot or doesn't, depending on pressure. This doesn't seem to be related to the mode (Auto, AV, TV, P, etc.) on the camera, nor to settings in the autofocus pages of C.FnII:Autofocus. The focus button in the dpp utility is greyed out, sometimes on MF and sometimes on AF. There doesn't appear to be a way to change it, at least in the software, and as there is no lens, I can't change the setting there. It isn't related to the remote shutter release, as the same behaviour occurs with the shutter release on the camera, and if I touch the LCD screen. I can focus manually, but I don't seem to be able to get really good focus at all. FWIW, it worked fine last year when I was using it with my compound microscope, and I'm using the same camera/microscope adaptor from Amscope.

Because the camera is on the microscope, using the * button or anything else that relies on using the viewfinder or per-shot buttons is not an option - it needs to be something I can set and leave alone - presumably whatever the settings were when it worked!

Thanks so much for any and all help!

Kit.

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patta
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Re: Camera Focusing Challenges

#2 Post by patta » Thu Oct 21, 2021 3:29 pm

Sorry I do not understand - how was the focusing working previously?
The camera is mounted directly on the adapter, no autofocus lens... how could it focus?

I use the camera 600D, it can Autofocus when tethered to computer with EOS utility; but only with an autofocus lens (...) and I need to enable focus (ON) in the live view panel. By default focus is OFF, and also turn off automatically after first focusing, you have to press on every time. Sort of bug? The ON in the panel may be the alternative to the " * " or the remote shutter half-press.

But on microscope I don't use autofocus as usually the camera has no lens; instead I enlarge the live view (lens below live image, "actual size window") and focus manually.
Not elegant but works too..
EOS_Utility_autofocus.jpg
EOS_Utility_autofocus.jpg (88.53 KiB) Viewed 1926 times
Last edited by patta on Thu Oct 21, 2021 5:13 pm, edited 1 time in total.

EYE C U
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Re: Camera Focusing Challenges

#3 Post by EYE C U » Thu Oct 21, 2021 3:59 pm

NO LENS NO FOCUS.

KitKestrel
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Re: Camera Focusing Challenges

#4 Post by KitKestrel » Fri Oct 22, 2021 2:21 pm

<sad sigh>. That makes total sense, and yet I must have been doing something because I have thousands of photos of microorganisms from last year using the compound microscope so there was no lens, and I used the EOS Utility/DPP4 to manage the process. I guess I must be remembering using the autofocus when I was shooting the non-microscope pix, and must have used the eyepieces to focus the microscope shots. Maybe my compound microscope is better calibrated for that kind of photography than my stereomicroscope. It's certainly easier - the compound diverts part of the light to the camera so I can still use both eyepieces to focus, but the stereo uses a mechanical device to close one eyepiece and divert all that light. Harder for me to sense the focus, and the image on the monitor doesn't seems to display in enough resolution to determine fine focus.

Thank you for your explanation.

Kit.

Hobbyst46
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Re: Camera Focusing Challenges

#5 Post by Hobbyst46 » Fri Oct 22, 2021 3:32 pm

In principle, the view should be focused with the microscope and not with any function of the camera, regardless of the type of adapter. This is definitely the case with the compound microscope.

Dubious
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Re: Camera Focusing Challenges

#6 Post by Dubious » Sat Oct 23, 2021 1:00 am

Too bad it can't work the way you described; but with your setup--camera back to adapter tube--to affect focus, the camera would need to vary the distance between itself and the objective, and clearly it has no way to do that. The best you can do is to adjust the camera/adapter (if adjustment is possible) so that the camera is reasonably parfocal with the eyepiece. Then, when taking a photo, you first adjust focus through the eyepiece, then tweak focus while viewing on the screen (if necessary), before clicking the shutter.

The EOS Utility's magnifier function Patta circled above can be useful when manually tweaking focus on the screen.

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