Question about the EX-25!

[totetuti]

what is the focus range of the EX-25 on the 50-200mm? Thanks!

[First Light]

It varies with the focal length (zoom) of the lens. Here is what the EX-25 manual says about the ZD 50-200mm f2.8-3.5 lens:

50mm --> 27.6 – 28.0 cm
135mm --> 48.9 – 53.9 cm
200mm --> 88.5 – 195.9 cm

You must manually focus the lens with the EX-25 attached. In fact, the only lens that you can still autofocus while the EX-25 is attached is the ZD 50mm f2.0 macro lens.

[totetuti]

Thanks!... the extension tube use is just simply too limited; i guess i\'ll just buy the 50mm macro...

[iROK]

In fact, the only lens that you can still autofocus while the EX-25 is attached is the ZD 50mm f2.0 macro lens.

ForReal??? :ohmy:
Is it for Optical reasons or is it the CHIP in the Tube that decides what it will Auto Focus with?

[llpoolej]

Are you sure? I have used the EX-25 many times with 50-200 and used AF.

This shot was done with that combo. I know I didn\'t manually focus it

Date Taken: 2005-07-09 09:16:41
Date Modified: 2005-07-09 16:12:36
Make: OLYMPUS CORPORATION
Model: E-1
Size: 800x600
Bytes: 210829
Aperture: f/4.5
ISO: 100
Focal Length: 158mm
Exposure Time: 0.0031s (1/320)
Exposure Program: Manual
Exposure Bias: 0
ColorSpace: sRGB

http://llpoolej.smugmug.com/photos/27716006-M.jpg

[First Light]

iROK wrote:
...Is it for Optical reasons or is it the CHIP in the Tube that decides what it will Auto Focus with?
I don\'t know. I don\'t see why it would be an optical thing. I think it probably has more to do with the shift in focus range and the way the lens and camera have certain built-in assumptions about how to adjust the elements in the lens based on the focus distance. Primarily, I\'m just going by what Olympus has written in their EX-25 manual. You can download it yourself from Olympus (http://www.olympusamerica.com/e1/sup_literature.asp) and read what it says.

llpoolej wrote:
Are you sure? I have used the EX-25 many times with 50-200 and used AF. ...
My guess would be that it might work some of the time but not all of the time and so Olympus says to plan on using MF for most lenses when using an EX-25. I use a ZD ED 50mm f2.0 macro a lot and I have to MF all the time because the DOF is very shallow and I need to manually adjust the focus point for artistic reasons.

The EC-14 is similar. They say to manually focus with it for the slower consumer-grade lenses. Why? Probably because there is not enough light to AF well when the EC-14 is used. It doesn\'t mean that you can\'t AF at all. Rather, it is just a general guideline so you won\'t buy the thing and expect AF to work as well as before.

Here\'s a rose that I shot this morning with my E-1 and ZD ED 50mm f2.0 macro. AF placed the focus point a bit closer than I wanted which would have put the center of the rose slightly OOF. So I tweaked it with MF.

http://fourthirdsphoto.com/components/com_simpleboard/uploaded/images/_C160004a.jpg

There are plenty of times when AF works okay. But there are many times when your creative requirements or environment will require MF.

[gunnerx]

I\'ve used AF with the 50-200mm all the time actually and find it to work quite well. I also have used nothing but AF with the 50mm macro and haven\'t been disappointed. It focused properly on a single snowflake.