from 15mm to 90mm focusing?...

[georgef]

Greetings fellow RFers...
I just bought a voigt 90mm last friday and tried it out over the weekend. I am not sure if its my eyes coupled with the short base of the RD1, but I may be getting front focusing or I may not be. I will follow up with a proper evaluation next weekend. I wonder though, if I do endeavor to re-calibrate the focusing as per the invaluable information that is available in this site: if I calibrate the focusing, do I have to choose between the wide or tele end, or should it work on both ends? Right now, my 15mm, 40mm and 50's focus perfectly. Am I running the chance I will throw them off focus?

I wanted to know your thoughts before I get into this operation.

Thanks in a dvance,
George.

 

[boilerdoc2]

Don't re calibrate. The 90 is too long for the short EBL of the Epson. Get a Megaperls magnifier for the eyepiece to help you focus the 90. And what do you use for the framelines?
Steve

 

[RichC]

The 90 is too long for the short EBL of the Epson

It's not, albeit it's at the limit wide open at f/3.5: http://www.richcutler.co.uk/r-d1/r-d1_05.htm

Using my Leica 90/4 wide open and focused on close subjects does need great care and an accurately calibrated rangefinder, owing to the wafer-thin depth of field.

 

[louisb]

Elmarit 90/2.8 lens

Elmarit 90/2.8 lens

OK, I still do not understand the issue with focussing using a 90mm lens on the RD-1. All the following shots were taken with my Elmarit 90/2.8. I do take great care at near distances and often use a high f-stop. However, as you can see, this is not always the case.

First shot was taken on a subject at approximately 10-15 feet from me with an aperture in the range of f5.6. This was shot RAW and sharpened post-processing. Estimated subject using the 50 frames and rangefinder patch.



Second shot was taken with the subject at no more than 6 feet, with a wide-open aperture. Also RAW with post-processing sharpening. Estimate the subject using the 50 frames and the rangefinder patch.



Final shot was at close to infinity at f/22. Used a Leitz 90mm bright-lines finder (which I find works quite well).



What am I doing wrong?

LouisB

 

[RML]

Yes, before you start to calibrate, make sure it's not the lens, your eyes or both that are causing an apparent mis-focus with that 90. Though a 90 may be properly focused on the R-D1, I wouldn't stake my life on being able to do it out of hand.

 

[RML]

What am I doing wrong?

It's not that yo do anything wrong. It's that we're not all as clear and sharp sighted, and that not all of us can focus very accurately, and that not all of us have got our breathing or hands and body under control, or have an accurate external VF, etc.

Try to focus that 90 from a tripod, focusing on a stationary object. Repeat and repeat, and try out different objects at different distances.

 

[Ronald M]

If all the other lenses focus properly, it is the 90 or you can`t not focus well enough.

 

[georgef]

Thanks everyone,
I had not had a chance to really try the lens, but I do remember someone telling me a while back that re-setting the focusing for the tele might throw off the wides, that's all! I find the RD1 is bright enough to focus the 90 clearly, but it sometimes seems to miss. I may be entirely wrong and have well-focused images throughout (or so I hope LOL)

Steve: I frame the 90 by eye, judging the centre of the 50mm lines...I have not devised a better method yet, and I did not find that inadequate yet.

I will post some shots tomorow.
thanks and cheers. george