While reading over the recent posts and came across another helpful insight. On my 4x5 Speed it appears the infinity stops are not even. When resting on the stops it appears the front standard is not parellel with the film plane. I'm new to Graphics and need some advice on correcting this. Should I set up on a tripod and aim on infinity(at least 1/2 mile) and determine which stop is correct. How can you see the descrepency? Will one side of the frame be out of focus when the other is on time. It seems that there COULD be a very small difference and is this readily apperent?? Thanks to everyone,you people have really helped with every step!

If you have found that the focusing scales on the camera are accurate, might it not be most straightforward to retract both infinity stops, adjust the track for infinity, loosen the lock on the front standard, and carefully determine the infinity focus by nudging the standard along the track by hand? That should tell you which of the infinity stops is in the right place.

The latch is designed to make an attempt to lock the standard parallel to the rails, but not a very forceful attempt, and it's easy to skew the front (as misaligned infinity stops will do).

The effect of this skew is the same as imparting a very slight "swing" to the front of a vew camera. As you say, it will cause the focal plane of the lens to intersect the back at a slight angle, so a row of objects all at the same distance in front of the camera will produce images that exhibit different sharpness from left to right. The sharpest one might be anywhere across the field; if the lens were accurately swung on its vertical axis, it would be in the middle.

The odds are that if you have been happy with the photos the infinity stops are close enough; if they are not perfect it will probably not matter. However they should be as good as you can get them. You will need a small machinists square, or some other small edged square which you will align with the inner edge of one of the yoke rails and the bottom edge of the front standard. This check will tell you how far out you are. You did not specify whether your camera is a top or side RF; this will affect how you will adjust the infinity position if that is needed. For now just square the infinity stops and take the camera and tripod out to check the infinity setting. Be sure to use a VERY distant object; I use one of the local TV antennas which is about a mile away. Focus on this distant object carefully, and then examine the ground glass image critically with a loupe to see if it is sharp. Prove it to yourself by focusing via the groundglass and now check the RF image. If they are not in agreement the starting position of the RF will need to be adjusted. This is easy on the side RF cameras; there is a large eccentric adjusting screw on the inner right side of the yoke. You will not see it unless you rack out the yoke most of the way. Use a screwdriver to make small adjustments to bring the RF/GG into agreement. This can be frustrating as the adjustment cannot be made while examining the image, but must be done on a trial basis. Once they agree, focus on infinity and lock the yoke. Now check the alignment of the focusing scales on the left side of the yoke, and adjust the inner scale as needed to get them to match at infinity. You are done.

The top RF is different; there is no eccentric to make adjustments with on the yoke. Coarse adjustments are made by sliding the connecting tab on the left side of the yoke, but you probably are not going to need to make coarse adjustments. The ones I set up were done by aligning the RF at infinity, and then sliding the lens along the standard to focus the GG image. Then lock the front standard and check again. If you did not move the front standard the GG image will still be sharp and you can slide the infinity stops (which you should have loosened at the beginning of the process) up against the front edge of the standard base. This is the point where you check the square again. If all is well adjust the focusing scales as described above.

Check the RF/GG agreement at two or three positions before you run film through the camera.


It sounds worse than it is, and unless your front standard is grossly out of square you probably will not have to adjust anything.


<font size=-1>[ This Message was edited by: disemjg on 2004-01-25 14:01 ]</font>

What has this thread to do with lens/shutters? Should have been posted in Speed Help.

Turn focusing knob until rails (yoke) is fully retracted into the camera body then turn the focus knob until yoke (rails) move foward approximately 1/8 inch and set focus lock. Move lens/front standard until lens is focused at infinity on the ground glass with standard locked. Set infinity stops, focus scales, Range Finder to this position.

_________________
While a picture may be worth a thousand words, a quality photograph is worth a million.

<font size=-1>[ This Message was edited by: 45PSS on 2004-01-25 18:09 ]</font>

<font size=-1>[ This Message was edited by: tsgrimm on 2005-06-13 07:24 ]</font>

Agreed! The question concerned infinity stops and their relation to focus. Last time I looked, focus was a function of the lens. The title of this forum is "Lenses Help" (not "lens/shutters"), therefore the gentleman's query is appropriately placed here.

The shoe fits again....

<font size=-1>[ This Message was edited by: Henry on 2004-04-10 18:26 ]</font>

Yea, thanks guys. I always thought the lens standard held the lens.

I actually find it very funny when someone says this belongs there, I have run a great number of message systems, including one that took over 1.5 million visitors a month and have never quite run into this type of put it in the right place attitute...


Not being critical, just find it comical..

Dave

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