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07-14-2018, 07:23 AM   #1
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645D Anyway to Zoom in to Focus ( MF) to make sure Image is in Focus Before taking i

I am trying to Nail MF when Taking Portraits on the persons eye. Is there any way to do this and not just MF the lens till I think its in Focus? Thank you
I was thinking of buying the Split micro prism to make it easier to focus. I saw one for 100.00 plus 16 shipping Not sure if it will do what I want. Thanks Dennis

07-14-2018, 01:48 PM   #2
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QuoteOriginally posted by rollsman4 Quote
I am trying to Nail MF when Taking Portraits on the persons eye. Is there any way to do this and not just MF the lens till I think its in Focus? Thank you
I was thinking of buying the Split micro prism to make it easier to focus. I saw one for 100.00 plus 16 shipping Not sure if it will do what I want. Thanks Dennis
The 645D has no live view, so you're limited to focusing screens/magnifiers. Things got a lot easier on the 645Z, which does support live view, magnification, and so on.

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07-14-2018, 06:36 PM   #3
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In the movie/video world many zoom lenses are parfocal lenses, meaning the focus doesn’t change when zooming. In that world it was common to zoom in to the longest focal length so you can focus, then zooming back out to frame your shot. I don’t know if any of the 645 zoom lenses could work that way.
07-14-2018, 11:04 PM   #4
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645 zooms are parfocal. If I were taking portraits, however, I would use the 150mm lens which is not a zoom. The zooms are slow enough that they might be harder to focus anyway and some people might find the 80-160 lens intimidating.

07-15-2018, 03:24 AM   #5
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I can only speak for working with the 645Z. It's very difficult even using live view and magnification as the subject can often slight shift their position. Working at f2.8 on the 75mm gives a DOF of about 1cm so focus is critical and not possible without the live view, etc. When I have tried to focus through the viewfinder, the results have been poor. I think one option is to stop down to about f10 which gives you about 4cm DOF. This also allows for both eyes to be sharp if the subject is turned slightly. Of course the background will come into play more so you would need to think about that. The link below has been useful.

DOF simulator - Camera depth of field calculator with visual background blur and bokeh simulation.
07-15-2018, 07:43 AM   #6
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I appreciate the responses. I just ordered the AA-82 Microprism for the D I hope this will help with my focusing.
Thank you
07-15-2018, 02:47 PM   #7
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With my P67, I found the viewfinder magnifier really helps (although clunky to use) when using my split-image only screen when the subject doesn't suit the split-image (I much prefer the micro-prism screen). The 645 magnifier seems really expensive though by comparison.
07-15-2018, 08:26 PM - 1 Like   #8
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QuoteOriginally posted by rollsman4 Quote
I appreciate the responses. I just ordered the AA-82 Microprism for the D I hope this will help with my focusing.

Thank you


I have found I can focus very accurately with the microprism screen on my 645z.

Rick “more accurate than focus confirmation” Denney

07-16-2018, 12:49 AM   #9
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Are the replacement screens typically accurate as a simple "in/out" procedure?. I ask as I've occasionally had to shim the screens on Canon bodiies.

Bob
07-16-2018, 01:06 AM   #10
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QuoteOriginally posted by rdenney Quote
I have found I can focus very accurately with the microprism screen on my 645z.
I've also had good results just focussing through the viewfinder. Getting the right dioptre correction on the eyepiece is crucial of course.
07-16-2018, 02:36 AM   #11
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A couple of points spring to mind. Do correct me if I'm wrong. Does the AA-82 Microprism not have a central circle that splits. How would that work if your subject's eyes are not in the centre? Also it's very much miss if you attempt to get sharp images on the eyes with a wide open aperture by just using the viewfinder and standard screen.
07-16-2018, 03:34 PM - 1 Like   #12
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QuoteOriginally posted by Bob L Quote
Are the replacement screens typically accurate as a simple "in/out" procedure?. I ask as I've occasionally had to shim the screens on Canon bodiies.

Bob

Simple install. But I’ve never had to do anything with my Canon bodies, either, and I have a Maxwell screen in my 5D.

Rick “Soviet cameras are a different matter” Denney

---------- Post added 07-16-18 at 03:40 PM ----------

QuoteOriginally posted by Sandy Hancock Quote
I've also had good results just focussing through the viewfinder. Getting the right dioptre correction on the eyepiece is crucial of course.

On my 645z, the eyepiece is focusable. I think it is on my 645N and NII, also, so I would be surprised if the D is not.

Rick “focus the lines on the screen sharply, then focus the camera” Denney
07-16-2018, 04:24 PM   #13
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QuoteOriginally posted by rdenney Quote
On my 645z, the eyepiece is focusable. I think it is on my 645N and NII, also, so I would be surprised if the D is not.

Rick “focus the lines on the screen sharply, then focus the camera” Denney
Yup, the D has dioptre correction from -3.5 to +2. I find the screen on the D is bright enough to use the ground glass for focussing - if shooting quickly it's easier than trying to chase the focus confirmation indicator while framing.
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