Super Ricohflex: Does Focus Stop at Infinity?

[Kahlil H.]

I just bought a Super Ricohflex that needs a focus recalibration. I've got the thing apart and I've set the viewing lens at infinity, but I don't have a focusing screen to check the taking lens.

Do Richoflexes typically stop at infinity? I tried using a thin piece of tracing paper in lieu of a focusing screen and it looks kinda like it's infinity is in focus at the far end.

thanks!

 

[Dali]

Adjusting focusing for a Super Ricohflex is pretty simple if you have a spare screen to check the taking lens. Yes, it should stop at infinity but if the lens is not properly screwed, it doesn't help...

Too, I would advice to set both viewing and taking lenses at short distance as adjustment accuracy is much better than at infinity. Once the short distance adjustment is done for both lenses, you can check at longer distance with a contrasty target.

One thing to keep in mind: Super Ricohflex screen are pretty bad and adjustment should be done with high magnification (ie an eyepiece or at least a lens as magnifier) to make sense.

 

[John Koehrer]

Setting focus at a near distance doesn't guarantee infinity will be on. That's why any test targets are used at infinity. If you don't have a test target use something you can see clearly at a city block or two away. Something like a radio antenna or flagpole works fine.
You may try oiling your tracing paper to make it more translucent, a drop or two of cooking oil will do.

 

[Dali]

John, to paraphrase you, I would say that setting focus at a infinity doesn't guarantee near distance will be on. Close distance setting is more demanding (shallow d.o.f.) but more easier (I have a 2 dimensions target with contrasty patterns to aim at). Most of the time, near distance setting gives good result at infinity and doesn't need further adjustment (unless like with M39 Leica-like camera you have a mirror adjustment for infinity. Then you have to switch back and forth between both setting to get the job done).

 

[Kahlil H.]

I'll give the oiled paper a try, I suppose something more rigid would be more appropriate. I'll also check close focus. Thanks! Looking forward to the first roll.

 

[JPD]

A simple viewing screen can be made of a piece of transparent plastic (cut from a CD case for example). Then tape matte scotch tape on one side. Voilà!

 

[Andrew Moxom]

I found my super ricohflex had a bit more travel after I focused at inifinty when I calibrated mine. I used a spare 6x9 ground glass screen to focus on infinity with the interleaving cog wheels removed. I then placed the taking lens cog back on, and locked it with the grub screws, and taped it. I then adjusted the viewing lens using the hood and magnifyer. After doing that, I carefully placed the cog onto the viewing lens so that the infinity mark was at the top. After screwing that cog back on, and removed the tape, it works fine, but there is some overtravel in mine. It close focuses fine also.

 

[Shangheye]

OK here was my trick since I did not have a spare ground glass either....I took out the viewing screen from the camera, used it on the back to find infinity at the film plane using the taking lens (I used tape to hold it in place). When that was set, I replaced the viewing screen and set that to infinity using the viewing lens. Set the camera on a tripod, helps if you have someone holding down the shutter on bulb, makes sure you have chosen a true infinity distance when you are doing the taking lens infinity...took me 15 minutes, and it is as sharp as nails. Otherwise follow Andrew's instructions!

No it does not always "stop" at inifinity so I don't suggest that method.

K

 

[Shangheye]

I would also add that when you set the GG on the back at the film plane, tape it such that the GG is in line whith where the film plane would be...K

 

[Andrew Moxom]

I would also add that when you set the GG on the back at the film plane, tape it such that the GG is in line whith where the film plane would be...K

Kal is also correct on this. I used a 6x9 GG screen that was taped to make sure it was directly on the rollers in the film gate. I also taped the camera back open, and I used a locking cable release with the shutter on bulb and aperture wide open to focus at infinity.

Workes like a champ now.

 

[Kahlil H.]

OK here was my trick since I did not have a spare ground glass either....I took out the viewing screen from the camera, used it on the back to find infinity at the film plane using the taking lens...

K

I will do this. I tried to take the screen out of my pentax 67, but when I did so, I could not figure out how to get it to sit flush with the film plane. This should work.

Thanks all for the advice!

 

[John Koehrer]

John, to paraphrase you, I would say that setting focus at a infinity doesn't guarantee near distance will be on. Close distance setting is more demanding (shallow d.o.f.) but more easier (I have a 2 dimensions target with contrasty patterns to aim at). Most of the time, near distance setting gives good result at infinity and doesn't need further adjustment (unless like with M39 Leica-like camera you have a mirror adjustment for infinity. Then you have to switch back and forth between both setting to get the job done).

If it works for you, fine. I was taught to adjust for infinity & let close focus go unless it was a zoom lens, which could be set for both.

 

[Dali]

Infinity, I don't know what it means exactly: 200 times the focal length, 500 times, 1000 times, something else???

2 meters, I know what it is, it is 2 meters and it is easy to measure. That's my point.

Once again, focus accuracy is more critical at short distance as d.o.f. is shallower than at "infinity".

 

[Shangheye]

Infinity, I don't know what it means exactly: 200 times the focal length, 500 times, 1000 times, something else???

2 meters, I know what it is, it is 2 meters and it is easy to measure. That's my point.

Once again, focus accuracy is more critical at short distance as d.o.f. is shallower than at "infinity".

Dali...if you look at your focus ring, you require less movement at longer distances to be out of focus...i.e. you need to turn the ring more between say 1.2 and 1.5m than you do between 10m and infinity. That means that either you need to be incredibly accurate in measuring the distance to the image you are focusing to when calibrating at near distance or you could be significantly out (since the focus ring has to move further for shorter distances)....that is not so at infinity.

Believe me I have tried both methods....one works (infinity)...the other is a nightmare. I am open to be convinced, if you give me your methodology, but I can only agree with other posts...calibration of the lenses using infinity is the best way.


Rgds, kal

 

[Dali]

Kal, that's why you need to be precise at short disance to avoid trouble at infinity. With a tape meter, you can estimate 2 meters +/- 0.005 meter. As long as you have a contrasty target (black and white stripes for instance) and an eyepiece to magnify the screen image (a 50mm lens for instance), I don't see where the trouble is. Once again, at short distance, the shallow d.o.f. is a good focussing aid you don't have at long distance.

 

[Shangheye]

Kal, that's why you need to be precise at short disance to avoid trouble at infinity. With a tape meter, you can estimate 2 meters +/- 0.005 meter. As long as you have a contrasty target (black and white stripes for instance) and an eyepiece to magnify the screen image (a 50mm lens for instance), I don't see where the trouble is. Once again, at short distance, the shallow d.o.f. is a good focussing aid you don't have at long distance.

I have to accept that you have tried it and it worked for you with whichever camera you were using. The main issue with what you just described with calibrating the Ricohflex specifically, is that after focusing the taking lens I then have to slip on the focus gear on to the viewing lens at that precise distance setting. For infinity that is easy, becasue there is a focus stop and quite simply, infinity is as far as the focus ring will go...for intermediate distances, you would have to literally slip on the gearwheel at that precise distance on the scale...each to their own I guess

 

[Dali]

This is more or less what I did twice with Ricohflex cameras.

 

[adamc]

help with focus?

I'm trying to calibrate the focus on my newly aquired Ricohflex. The taking lens was easy to do, but I'm having trouble getting the focusing lens to focus at infinity. It seems that the lens needs to be closer to the mirror in order to focus at infinity, right now when I put the lens in and push it as far back as it goes, it's focused at around 2.5 feet. From there, it only rotates out (focusing even closer).
I attached a pic of the parts from the viewing lens. What I've been doing is screwing #2 onto the lens, putting that in the camera body (already too far from the mirror). Then on the inside of the camera, I slip #3 and #4 on the lens and tighten them down. If this worked then I would put #5 on, but it doesn't...does anybody know if I'm missing something?

 

[Shangheye]

I never had to take mine apart this far..you could PM Andrew Moxom who I think Did....at first sight i can't see what you are doing wrong. Rgds, K