Serious Telephoto Focus Problem on R-D1

[Kevin]

Hi All,

I haven't really used my Tele-Elmarit-M (Thin, Germany) for a number of years on any M-Mount cameras but recently I tried it out on my R-D1 and got severe out-of-focus results at all focusing distances.

Today I set up a 45-degree tape measure shot and close focused (approx 1 metre) targeting the end of the tape measure.

The result is a front focus of approx 12-14 centimeters.

Does anyone have any calibration advice for me in Germany? I don't know if I should send the lens to Solms with the R-D1 ... they might not like that!

Best Regards
Kevin

 

[BillBingham2]

It's the effective base length of the R-D1, it's way short for this fast and long of a lens close up. I do not remember which magnification the R-D1 is, but I think it's the same as the R and R2.

Take a look here for the RF EBL (Range Finder Effective Base Length) info:

http://www.cameraquest.com/voigtchart2.htm

and here for info on focal length of lens vs effective base length:

http://www.imx.nl/photo/technique/technique/page49.html

The range finder was just not made for this type of lens.

B2 (;->

 

[Al Kaplan]

I'd be looking at the R-D1 as the problem. It's next to impossible for the lens cam to get screwed up. Rangefinders can get out of adjustment. Did you check another lens on the body?

 

[laptoprob]

... and did you check the lens on another body? I'd suggest starting with your M6. I test with a split screen from an SLR pressed against the film rails. In the split screen you can judge focus very accurately.
Wide open will be very challenging, but stopped down it should work OK. So using the TE wide open is aiming too high, but for testing OK.

 

[splitimageview]

RF accuracy chart here. The RD1 needs a magnifier to handle a 90/2.8, assuming the RF is not out of whack.

http://www.rangefinderforum.com/forums/showpost.php?p=769052&postcount=44

 

[sonwolf]

Using lenses longer than 50mm on the R-D1 can create focus problems, if your camera can focus normal and wide angles lenses, consider the following before assuming the lens is the problem:

- The R-D1 cannot accurately focus an aperture wider than f/2.2 on a 75mm lens, without help of a magnifying eyepiece. The rangefinder base is too short to accurately focus faster lenses.

- Focus the lens from both minimum focus distance and infinity, then compare the two images. On my R-D1, focus tracks more accurately from minimum focus distance, rather than infinity. I can achieve fairly accurate focus by first setting the lens to absolute minimum distance and then setting the correct distance. If I track focus back from infinity, while using a wide aperture, the image will usually be out of focus.

- Use a eyepiece magnifier to assist in achieving more accurate focus.

 

[uhligfd]

Where exactly was the 100 cm mark on that tape? I hope it was aligned with the sensor plane. Also, your view is from above and the triangle inequality does apply to sideways measuring devices....

So, start again with an object that is in a plane parallel to the sensor plane exactly 100 cm in front of that sensor plane. Or did you measure the "focus" via the rangefinder mechanism? Then it is out of sync.

 

[Kevin]

Thanks for all the replies!

In the meanwhile I tested my Heliar 75mm at 2.5 and 2.8 apertures and it front focuses too. Also my Nokton 40mm front focuses slightly at close distances.

It is strange that I have had no problems with any of my 35mm lenses or the 28mm Ultron.

Maybe those lenses front focus too and I just don't see it.

How does a calibration service work? Do I send my R-D1 and all lenses to a technician? Or is this something I can fix myself?

I have already adjusted the rangefinder alignment twice.

Best
Kevin

 

[Al Kaplan]

The 28 and 35 probably have enough depth of field to mask the problem. The camera and one lens should be enough, but odds are they can do it with one of the lenses they have on hand. Ask them!

 

[BillBingham2]

Kevin,

Look at the shots with the 28 and 35, stretch out the tape and I bet you will find your camera is front focusing there too. Figure this out by plotting the ends of acceptable focus and find the middle.

B2 (;->

 

[Kevin]

Thanks Al!
If only I knew where to ask .... Epson Repair in Paris?

 

[Kevin]

Kevin,

Look at the shots with the 28 and 35, stretch out the tape and I bet you will find your camera is front focusing there too. Figure this out by plotting the ends of acceptable focus and find the middle.

B2 (;->

Okay, I'll give that a try now.

Do you think that my having adjusted the rangefinder patch caused the rangefinder to go out of alignment?

 

[BillBingham2]

Not sure, i've never had to open up any Bessas that I've owned. Perhaps someone else has first hand experience with one. Anyone? Anyone? Anyone???

B2 (;->

 

[LCT]

Due to the short base length of the R-D1's rangefinder, 90/2.8 lenses cannot be focused accurately at full aperture w/o a 1.3x magnifier. I would redo the test at f/4 before touching anything in the camera.

 

[laptoprob]

Due to the short base length of the R-D1's rangefinder, 90/2.8 lenses cannot be focused accurately at full aperture w/o a 1.3x magnifier. I would redo the test at f/4 before touching anything in the camera.

Or just try a few times, focussing everytime freshly. With an average of those focus attempts you can average. Thus you can rule out the rf inaccuracy. So having a too long and too fast lens can aid in finding the problem.

 

[Kevin]

Hi again!

I just tested my 35mm Nokton 1.2, 40mm Nokton 1.4, 75mm Heliar 2.5 and 90mm TE 2.8.

In these tests there is no obvious front focus except for the 90mm so I am inclined to believe that this lens wide open is not going to work very well on the R-D1. Thanks for all the comments explaining why this is so!!

I've attached the results of my quick test. I think that my camera has focus backlash but when I focus down from infinity and stop at the intended focus point it is accurate.

Next I will test the 90mm on my M6 and scan the results!

Best Regards
Kevin

 

[LCT]

Using a lens out of the accuracy range of the rangefinder is the worst way to test both IMHO.

 

[Kevin]

- Focus the lens from both minimum focus distance and infinity, then compare the two images. On my R-D1, focus tracks more accurately from minimum focus distance, rather than infinity. I can achieve fairly accurate focus by first setting the lens to absolute minimum distance and then setting the correct distance. If I track focus back from infinity, while using a wide aperture, the image will usually be out of focus.

Thanks for this and all the other replies. Without 75mm and 90mm framelines on the R-D1 I'll just stick to using these lenses on the M6.

For me it seems I get accurate focus on the R-D1 for all focal length lenses (except the 90mm) if I first set the lens to infinity and immediately stop at intended focus.

 

[Kevin]

At 1 meter focusing distance (as marked on the lens barrel of the 90mm) the M6's film plane is exactly 100cm from the intended focus point. On the R-D1, however, the actual distance is 106cm.

That confirms it, folks!

 

[LCT]

...That confirms it, folks!

Just confirming that you chose too wide an aperture IMHO.