Details of Manual Focusing with an "ist" or "Evolt"

Trying to verify focusing details of older manual focus lenses on

an "ist" or "Evolt". For example, I understand an "ist" will indicate

in the viewfinder "focus spot" when the older manual lens is focused

properly. Can't find that same capability with the "Evolt", am I

missing something? Regards.

Do you mean Pentax *ist? The focus indicator is close approx only, never to be exact. For precise manual focus, you still have to rely on the viewfinder. For that *ist D/DS/DS2 have the edge due to 0.95x viewfinders. Olympus bodies are really nice, but can't help with the small viewfinder as the CCDs are small.

Thanks for the quick response Alan. Yes, I was referring to the Pentax "ist" and the Olympus E500/300 Dslr's. Wanted to make sure I understood some of the differences.

 

So.. the Pentax autofocus operates independently from the lens (AF system is in the body) and the Olympus autofocus system is in the lens?

 

Regards.

Haven't used an E300 enough to say much about manual focus with them.

 

The Pentax *ist DS has an excellent viewfinder and is easy to focus manually. The AF

system provides focus confirmation ... testing, I found it to be accurate enough for

focusing an f/2.8-f/4 lens with reasonable consistently, but not for a faster lens wide

open. The AF sensor used for focus indication is always the centermost one ... which is

annoying because it lights both the green indicator at the bottom of the frame and the red

indicator on the center of the frame when it senses focus locked in. I usually use the

Custom Option to turn off indication on screen when using manual focus lenses; that

leaves just the green indicator which is easy to use or ignore as you prefer.

 

Godfrey

The AF sensor system is in the body on both systems.

 

Pentax drives the focusing in the lens through a mechanical coupling to the body. I'm not

sure about Olympus, whether they have in-lens focus motors or not. I would expect they do.

But this has little to do with whether they provide focus indication with a manual focus lens.

 

Godfrey

I know very little personally about the Evolt,(Have E-1 with the new ED Zuiko lenses and I do love my autofocus with a manual tweak capability in the lens's internal "motor"(note );still I have read a lot online from those who use the E300,E500. There is only a mechanical ring connection with an adapter for manual focus lenses on the Evolt or any 4/3 system models ( A buying issue for you, just wondered for the sake of wondering-?.)Maybe got much great legacy glass around? Evolts have no adapter for FD lenses BTW at present,but mount disatances seem to permit use of a number of legacy glass and they are listed on the web)

Unfortunately,manual focus is manual in every sense with no,zero,aid or help in the viewfinder except the actual image you see on the focus screen that you are using with the OM or similar legacy lenses. This article will not be a wasted read in your research,John,as it may have the answer in there:

 

http://www.wrotniak.net/photo/oly-e/any-lens.html

Thanks for the info Godfrey and Gerry. As you may suspect, I'm trying to choose an inexpensive dslr which can use different vendor prime legacy lenses in manual mode. The "ist" or "4/3 Oly" body features will help determine the choice.

 

After reading some of Wrotniak's info there are some interesting compromises when using the old lenses with the 4/3 system and similar situations with the "ist" as well I'm sure. What was most surprising though was the table showing the Canon FD flange-back distance and no reference to any adapter for the lenses. My old FD's are really "dead-ended".

 

I'm going to procrastinate and investigate some more stuff before I decide. Thanks again for the help. Regards.

Unless someone makes an adapter, yes, the FD lenses are a total dead end. It's too

expensive to custom adapt them one at a time.

 

The Pentax DSLR bodies work well with Pentax M42 mount lenses with no issues other

than that the lenses must be stopped down manually for exposure metering and making

the exposure. They also work well with early series K-mount lenses that do not have the

"A" setting on the aperture.

 

There are few adapters to use other mounts on the Pentax bodies, however, because the

mount register is one of the deeper registers and the bayonet flanges are a little difficult

to work around.

 

Godfrey

The E-volt does not provide the in-focus indicator spot when using older manual focus glass using an adapter. It only provides this when a current lenses, having an electronic linkage, is used.

 

In practice, on my e-300, I don't have any issue using the viewfinder to focus manually, when using either a fast 50mm, or a longer telephoto lens, even with out the in-focus dot indicator being active.