Pentaprism viewfinder and used "pro" gear - really better for manual lenses?

Question

I currently use an Olympus E-520 with an adapted Tamron 35-135 (manual lens from the '80s), and manual focusing is very difficult and hard to get right. Looking in the viewfinder, spinning the focus ring does not really affect the image much and I cannot make out the differences between a sharp and blurry image. The diopter is set right and the only way I can take a sharp image is to use Live View to enlarge the centre and focus carefully.

Even with my kit lenses and AF, I still cannot tell the small differences between whether or not an image is completely in focus or not. However, with a film SLR (even without looking at the split screen guides) I can see quite clearly how sharp the image is. The problem here is that the pictures look fine onscreen, but when I zoom in things gradually get blurrier - at 100% things don't look that good unless I actually use Live View.

I'm now looking at used equipment such as the Nikon D200 (older but still a good camera) and the newer Canon 40D. Both of them cost around the same secondhand, and have suppossedly brighter pentaprism viewfinders. They also have electronic aids (lights) that suppossedly can determine whether or not a manual lens is in focus, whereby my Olympus has none. I also like their better ergonomics and control.

Is MF performance really improved on a "pro" camera? Or is there another way to get good MF without upgrading at all? I use my Tamron most of the time and can't get good results by viewfinder alone unless I stop down my aperture (unacceptable in low light).

P.S. I've seen Katzeye split-screens and while they do they job they are simply too expensive for a simple piece of glass.

Answer 1

I have canon 40D and use M42 and Pentax K mount lenses. I had 400D before and I find the upgrade to a larger viewfinder VERY helpful. I use chipped adapters so I get the focus dots and they really do work. Even better is that 40D is built to take different focus screens, so it is easy to change them (takes 10secs), and such operations can impact AF system, but you get a menu setting to compensate.

You might want to interchange them based on situation, as there is no free lunch. more precise means darker, because it diffuses the light more. I dont use katzeyes because they black out at lower apertures and they obstruct your view. Focus screens that improve your perception of focus are darker than normal , so you want the brightest viewfinder you can get.

Itemized benefits of a "proer camera":

1. Brighter is better! - easier to see focus on a bright image. especially with precision focus screens you need it brighter, because the screen makes it darker.

2. Bigger is better! - read on the DOF and perceivable focus as a function of viewing size. 100% crops almost always look horrible while the downsized images are nice - because small size hides all the mistakes, such as out of focus.

3. Interchangeable focus screens with matching menu setttings: adapt to the situation without screwing your af system.

4. not really about the camera, but focus screen aids are optimised for F2.8 or faster lenses. zooms arent usually that bright, and it might make it harder to judge focus! go Prime.

as a side note: vintage lenses are awesome, but back then they didnt make zooms really well. So it is better to go for the primes with good review on pentaxforums lens review section.

Also note that if you go too pro (full frame) you might damage your mirror, unless you adapt the lenses.

Answer 2

I wouldn't classify the pentaprism vs pentamirror as being primarily an aid to manual focus, but focus confirmation is very handy (though I believe it is also available on lower end Nikon and Canon cameras). The big advantage of a pentaprism is that it is bigger, brighter and gives better coverage of the area of the sensor, so you have a better idea what you are shooting, particularly in low light. It's also helpful when trying to estimate depth of field since stopping down the aperture greatly reduces the amount of light getting in.

I suppose it probably does provide some aid, since it is brighter and clearer, but if MF is your only concern, I'd be more concerned about getting better lenses, a split focusing screen and AF points that support focus confirmation.