Crown Graphic focus with new lens

[campy51]

I picked up a Nikkor-W 135mm lens and want to replace the Xenar 135mm that came with it. The Xenar rangefinder and gg matched but with the Nikkor the focus is way off when lens board is set to the rail stops. Playing around with it I set the focus rail to 6 feet and set a target to 6 ft. and pulled the lens out until it was focused on the gg and the rangefinder seemed to match. I guess my question is if I move the bed stops to the new position is the camera set up to use the rangefinder cam from the Xenar? Was my method all wrong since I didn't use infinity? I should probably also ask if the Nikkor would give better results than the Xenar. Not that I was unhappy with the Xenar but bought a Nikkor-W 135 and a Fujinon-W 210 at a decent price.

 

[Leolab]

campy51

i would check that the rangefinder and ground glass match at multiple focus points (infinity, ~10m, and close-up). If they dont match-up the cam that is in the crown graphic is not usable for the Nikkor lens.

as far as Nikkor vs Xenar goes, the Xenar is a pretty good lens but is now pretty dated and is a Tessar design. Stopped down in aperture f22+ the differences may be subtle, but wider open, I would expect the Nikkor to be sharper and better in corners. The Nikkor also has a larger image circle allowing additional movements, the Xenar is restricted in enabling movements since it just covers 4x5.

I would use the Nikkor personally over the Xenar, even if the RF of the Crown does not work well with it. You can move the infinity stops so at least you can focus at infinity without using Ground Glass, and for other more demanding applications (closer focus, wide open use...) I would just use ground glass, or tape a piece of marked cardboard on/near the rails that has the accurate focus scale for the lens on it which can save some time.

My experience with the RFs on these is that they dont inspire too much confidence in thier accuracy, and if i’m shooting 4x5 i dont want to waste film by being off on my focus, and i’m not in a big hurry, so ground glass is better, RF is more useful for press-type use when you need to capture a scene rapidly.

 

[Donald Qualls]

Leolab has the right idea, but two lenses of the same focal length ought to have the same relationship of bellows draw to focus distance (i.e. be compatible with the same RF cam) once you have the infinity stops set correctly.

 

[Dan Fromm]

Leolab has the right idea, but two lenses of the same focal length ought to have the same relationship of bellows draw to focus distance (i.e. be compatible with the same RF cam) once you have the infinity stops set correctly.

Not necessarily. The focal lengh engraved on the lens' (usually on the trim ring or edge of the front barrel) doesn't always match the lens' actual focal length. That's why Graflex Inc. made so many cams for the top rangefinder Graphics.

OP, the Kalart RF manual can be downloaded from https://onedrive.live.com/?authkey=!AMvNyd9CqLT7ul8&id=8D71BC33C77D1008!13955&cid=8D71BC33C77D1008 I don't know where to look for a Hugo Meyer RF manual, if that's what your camera has.

 

[Ian Grant]

It should just be a case of moving the Infinity stops a s long as the FL's are very close. There's also adjustment of the fitting to the rear of the trackbed on teh left below.

Dan, I did find something years ago on adjusting the Hugo Meyer range-finders, the suggestion was these were the most adaptable. There's one on my pre-Anniversary WA special calibrated for a 90mm lens. I can't remember where I found the information it was around 12 years ago now.

Ian

 

[BrianShaw]

Having done a similar lens swap on a SuperGraphic... I swapped back to the factory-provided Optar and haven’t been disappointed. That was about 1980.

 

[Sirius Glass]

Take a look a the article on range finder adjustments at www.graflex.org.

 

[138S]

I picked up a Nikkor-W 135mm lens and want to replace the Xenar 135mm that came with it. The Xenar rangefinder and gg matched but with the Nikkor the focus is way off when lens board is set to the rail stops. Playing around with it I set the focus rail to 6 feet and set a target to 6 ft. and pulled the lens out until it was focused on the gg and the rangefinder seemed to match. I guess my question is if I move the bed stops to the new position is the camera set up to use the rangefinder cam from the Xenar? Was my method all wrong since I didn't use infinity? I should probably also ask if the Nikkor would give better results than the Xenar. Not that I was unhappy with the Xenar but bought a Nikkor-W 135 and a Fujinon-W 210 at a decent price.

Here you have the intructions for the Hugo Meyer

https://graflex.org/helpboard/viewtopic.php?t=6319
https://graflex.org/speed-graphic/hugo-meyer.html


I've been adjusting a Kalart in a Graflex, but not an H.M.

Just let me recommend that this operation has to be done with a lot of calm and accuracy

Iterate several times the procedure, use max aperture in the lens, and a powerful loupe (x8 or x12) for the ground glass.

Usually Ground Glass cannot display the maximum sharpness of the lens, find the points with a bit more or less bellows extension where you see a bit a focus miss and take a bit the midpoint, like when focusing a View camera. As you stop the lens DOF increases and any inaccuracy has less importance, but have a good result with wide apertures you have to nail the calibration.

The average Nikon W should be optically superior to the average Xenar, specially in the corners while wide open. Still the Xenar has a suberb bokeh, with a very smooth bokeh, probably many would prefer the Xenar for portraits, while the W should sport a very effective multicoating.

Anyway, as always, peak performance can be irrelevant in many situations...


For the Record:

Adjusting Hugo Meyer Rangefinders
The Hugo Meyer rangefinder is found on many Speed Graphics. It was offered as an alternative to the more common Kalart rangefinder on both civilian andmilitary models. These rangefinders can be identified by their oblong windows, Kalart rangefinders all have round windows.

If the rangefinder is sticky it should be removed from the camera and the cam surfaces cleaned. Removing it requires removing the actuating arm from the shaft and removing the four screws holding the rangefinder body to the camera. There is a torsion spring associated with the actuating arm, be careful no to loose it and note its position.

The cover plate on the camera side is held in place by a single center screw and locating pins at top and bottom. Removing it exposes the actuating cams. They should be cleaned with a suitable degreasing solvent like lighter fluid (Ronsonol) and re-lubricated with a very little light oil.

The mirrors can be accessed for cleaning by removing the windows. Each is held in place with two small screws, one at the top and one at the bottom. Use cotton swabs and lens cleaning fluid for cleaning.

To set up the rangefinder, use the follwoing procedure:

• First check the infinity setting for the lens. Generally Speed Graphics are set up with the lens infinity stops set with the bed extended about 1/16 inch from it maximum rearward position.
• Focus the lens manually on a target at least one half mile away and set the infinity stops at this position.
• Set the eccentric on the camera bed, on which the actuating lever rides to its maximum forward setting, the slot will be horizontal.
• Set the camera up 36 inches from film plane to focusing target. I suggest using a target similar to the one used for Kalart rangefinders with a separate target for taking lens and rangefinder. The cross lines for the rangefinder are drawn at the same distance from the lens target as the rangefinder upper window is from the lens. This is to avoid parallax which can make adjustment impossible.
• Focus the camera carefully on the target and tighten the focus lock.
• Hold the actuating lever against the cam and tighten the lock screws.
• There are three adjustments on the rangefinder. Two are located under the long model number label near the inside edge. This is held in place with two screws. It is not necessary to remove the screws, just loosen them and the label will swing away exposing slots through which the adjustments can be reached. The adjustments are made with a 1/16 inch Allen key. There is a lateral coincidence adjustment on the side of the rangefinder.
• With the camera set at 36 inches adjust the lower adjustment for coincidence. Then focus the camera on a target at infinity and adjust the upper screw for coincidence. Repeat these two adjustments until there is no further change.
• Check in middle distances for coincidence.
• Check the lateral adjustment at infinity before doing the rest of the adjustments.

The procedure automatically adjusts the rangefinder for the focal length of the lens used.

 

[campy51]

I have the top rangefinder not the Kalart.

 

[Dan Fromm]

Well then you need a cam for the Nikkor-W. Instructions for making one here: http://www.southbristolviews.com/pics/Graphic/graphicmanuals.html See the camera's user manual for instructions re removing and replacing the cam.

 

[shutterfinger]

The Graphic rangefinder does not respond like the rangefinders in 35mm cameras. It has a movable mirror on a rotating shaft and a transparent mirror fixed at a 45° angle to the front of the camera. Infinity is set with a calibration cam. Every cam made for the Graphic rangefinder is referenced to infinity. As Dan stated lens are rarely their marked focal length. The Pacemaker cam list https://www.graflex.org/speed-graphic/top-rangefinder-cams.html has 5 cams for lens 3mm focal length either side of 135. The greater the difference between the actual focal length and the focal length the cam was cut for the greater the error in focus as you move from infinity to closer distances. Graflex did not cut cams for focal lengths less than .5mm difference. A true 135 cam used with either a 133.5mm or 136.4mm lens will be accurate to about 10 feet to 15 feet then the focus error will increase. A 135mm cam and a 132mm lens will start showing focus difference by 25 feet.
The Super Graphic cam will not work in a Pacemaker Crown or Speed.

The approximate focal length of your Nikkor can be found by measuring from the shutter/aperture blades to the ground glass with the lens set at infinity.

Dan, there are no instructions for making Pacemaker cams at SouthBristolViews, there is information for making Super Graphic cams.

The procedure for making new cams for the Super Graphic can be applied to the Pacemaker Graphics. Starting at infinity measure the distance forward the yoke moves and the cam height at each of these focus distances 100 feet, 50 feet, 25 feet, 15 feet, 10 feet, 8 feet, 6 feet, 3 feet using a factory matched lens and cam or a lens and cam that have been verified to be accurate. Measure the distance the cam moves from infinity to the maximum travel of the cam. Measure the travel of the yoke from infinity to the point where the cam actuator plunger at the yoke just stops moving. Divide the cam movement by the yoke movement to get the ratio of yoke to cam movement. Using a blank .032 thick brass blank that is .437 inch high and 1 inch long. http://www.southbristolviews.com/pics/Graphic/manual-pdf/TRFService.pdf Mutiply the distance forward the yoke moved for each focused distance by the cam to yoke movement factor then measure left from infinity on the blank then up to the height recorded for that distance then repeat for all focused distances then grind the cam down to the correct height and distance marks then test it.

 

[138S]

Hmmm.... I would suggest a shortcut to overcome the Cam/adjustments nightmare, and to be able to use both the Xenar and the W without having to adjust the Range Finder when swapping the lenses:

>> Flange focal distance of the Nikkor W is 133.8mm

>> Flange focal distance of the Xenar is 126mm

...so we only need to place the W lens 7.8mm farther with a hat top lensboard. something like this:



but done with a glaflex lenboard.

I would cut a big hole in a regular graflex lenboard and I would place a plating on it, with the outer surface laying at 7.8mm distance from the original lensboard. That plating would have a copal #0 size hole...

For a fine adjust we may use some ultra thin shims...

So this proposition suggests not touching the Rnage finder at all, but just making a custom lens board that holds the lens 7.8mm farther, fine adjustment with shimming, this is we focus infinity with the xenar, then we mount the W (placed in the +7.8mm extended lenboard) and we find the right "micro" shim to get perfect focus without modifying the bellows extension that was good for the Xenar...

Then we should check if focus is also matched for close subjects, in theory it should, dataheets state real 135mm for both... in practice, who knows ?

Perhaps the W can be provisionally placed in the xenar lensboard with a 7.8mm "shim" to test that possibility.

http://www.hyam.net/blog/archives/3961
http://www.kennethleegallery.com/pdf/Nikkor_LargeFormatLenses.pdf

 

[shutterfinger]

A second set of infinity stops and a focus scale will work also. A shim to sit between the back edge of the front standard and the infinity stops to position the front standard at the proper position for the W will work also. Fold the infinity stops down, pull the front standard out past them, fold the infinity stops up, insert the shim in front of them, slide the front standard back until firm against the shim and stops.

 

[campy51]

Thanks everyone but I think this is getting all too complicated so I think I will just use the Nikkor when using the gg and use the Xenar when I want to hand hold as a press camera. The knowledge on this site amazes me.