Medium format and focus issues

This is one reason I went auto focus with my 35mm gear. But on occassion I miss the focus on the subject with both my Pentax 645 and 6x7. How many people deal with this issue on their medium format cameras? The screen is bigger then 35mm, so by rights I should be able to get the focus more accurate. But I still miss it at times. Many of these times were on overcast or shaded days. I changed the screen in my 645 to a Beattie, but I still ended up getting a few bad shots.

What are people doing to get accurate focus on their cameras? For portraits depth of field is small to get the background out of focus, or for the lack of light with slow film. All I know is a couple good shots ended up being passed over for enlargements due to missing focus.

To add the focus is correct on my cameras in terms of the screens themselves, so its not an equipment issue.

I use split rangefinder screens in my Mamiyas, which helps considerably. I also focus the lens wide open and use the depth of field preview to check depth rather than focusing with the lens stopped down.

- Randy

Try shooting action on MF with a 110mm f2 lens, at f2. Fun! A bright screen + WLF magnifer sees me over. A good sense on anticipation is required, namely knowing where the subject will be, and good timing. I've not had anything out of focus yet, which is a suprise given that I'm dealing with +/- 6" in some circumstances. Also what @reellis67 said.

On my NC-2 finder I have a brightscreen accufocus (SP?). It flips out of the way when not needed. It's been pretty handy.

Mike

I have to say that despite Beattie screens being notably brighter than the original screens in my Bronicas, I didn't find them any easier to focus. The Maxwell screens I use now are to my mind much easier to focus and for the first time these would largely enable me to focus using the body of the screen alone.

That said I have and use a split image focus device in the centre of my screens. Further I focus before finalising composition, so if I need to I feel able to move the aim around till I have something with a strong vertical at about the right distance, even if that isn't central to my composition.

If I'm really uncertain about point of focus or dof on what I feel may be a useful shot, I'll bracket the focus distance too- but thats a rare event.

My focus issues with MF went away when I switched to a Maxwell 45 split and got a proper diopter.

Also, if you have a handy fresnel or split image available in the center area of the viewfinder and you frequently tilt the camera up or down to put that focus aid over the subject's face to focus, the simple act of moving the camera will change the plane of focus. If you have narrow depth of field this will frequently result in soft eyes. Auto-focus doesn't correct for this issue, it just takes practice and care.

Neal

The Bronica SQ-Ai is fairly easy to focus due to the bright screen and the split image microprismthing. My current P6X7 is hard to focus because the screen is very dark and only focus aid is a lowcontrast microprism. I seriously consider to get a beattiescreen as soon as I can afford it.
Cheers
Søren

Don't know about the Pentax 67 but one of my Pentax 645's eyepiece correction adjustment can easily get misadjusted. Also the 645's can have partial blackout of the split image/microprism collar with slower lenses or if the eye is not centered. In either of those circumstances, I've had an occasional off-focus photo. I wish I could blame the cameras for all my out-of-focus pictures but the fact is, we're all human and we make mistakes and sometimes poorly judge the accuracy of our focus. It's really noticeable when lenses are used at wide apertures, as you related.

braxus said:

But on occassion I miss the focus on the subject with both my Pentax 645 and 6x7. How many people deal with this issue on their medium format cameras?

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When I first bought my Hasselblad and 120mm lens I too was having the same problems as you. It was really irritating. However, as with everything, the more you use it the better you get. I got good enough that I was able to focus perfectly with my Hasselblad. After a few years though I kind of lost interest in photography and put it down for a while.

I've just started to pick up using the 'blad again and I'm finding the same thing as you. Some of my photos are out of focus. I need to practice again. I know this is an analog user's group, but I picked up a relatively cheap digital back and I've found that focusing on that sucker is harder than it's ever been.

So, like you, I need to "learn" how to focus again. I'm using the split image that came with my screen (I have the one with the grid lines). I also noticed that it's actually easier to focus with the non-bright screen (i.e. the one that came with my 500c/m). Everything looks in focus when you're not quite perfect with the newer Acute-Matte screen making it tough to judge focus. That's why I'm probably getting out of focus shots. You're probably in the same boat with your Pentax cameras.

Well, practice makes perfect. Practice a lot and you'll get the hang of it. Good luck!

My Bronica is truly ancient (an S2A), and the viewfinder is a bit dim. I usually avoid using the reflex eyelevel finder because of its dimness and because I wear glasses and can't see the full frame with it. With the waist level finder, I usually use the magnifying glass to get the best focus. With either, you sometimes have to search for a good object to focus on. Try for something with a sharp line and good contrast. The center spot and split image features in the glass (if you have them) are very useful when things get difficult. It isn't just the Bronica. All cameras sometimes get difficult this way. My Pentax 645 is bright and easy to see through, but the same subjects are troublesome.

Just asking. How are your eyes? I have a bad astigmatism and was having focusing issues (go figure). Now with a new prescription, I get it pretty much dead on the mark everytime. So, just an eye-dea. (Yeah, I know, HAR HARRRR)

Try a rangefinder. I too have split prism screens on my medium format SLRs, which are a big help, but I still find my Mamiya 7II quicker to focus.

David.

nathantw said:

.....

I've just started to pick up using the 'blad again and I'm finding the same thing as you. Some of my photos are out of focus. I need to practice again. I know this is an analog user's group, but I picked up a relatively cheap digital back and I've found that focusing on that sucker is harder than it's ever been.

.....

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Huh? Why would the back (film or digi) matter when focusing a 'blad? :confused:

Earilier this evening I was playing with my 503CXi with just a lens and no back (just the cap) to "practice" focusing.

copake_ham said:

Huh? Why would the back (film or digi) matter when focusing a 'blad? :confused:

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That's a really good question, but it's one that that's been brought up and discussed numerous times in other forums. I didn't know about the "problem" until I actually had to try it. It's the weirdest thing. However, the problem exists. Autofocusing rules the roost when it comes to digital. One theory about the focusing problem is that it's because digital is so sharp that there's not room for error. I kinda-sorta believe it but not really.

So, in my case it's just practice, practice, practice.

copake_ham said:

Huh? Why would the back (film or digi) matter when focusing a 'blad? :confused:
.

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A bad back might have the film plane wrong.

No idea how common or even possible this is but if the film plane is wrong you're in trouble.

I only have the WL finder on my Hasselblad, so to check focus I use the little flip-up magnifier. Then I flip the magnifier out of the way and double check the framing on the full ground glass screen.

If I take my time, which I'm more likely to do when using a tripod, I don't have any trouble focusing. However, it took a bit of practice when I first started using this camera and finder.