Help to determine if the aperture index is right, and if not, how to fix it.

[StuartR]

Anyone have any experience setting the aperture index on a 4x5 lens? I bought a used 90mm lens from KEH and it came with a copal 1 shutter, but the aperture lever is on the bottom (which means I cannot mount it on a Linhof board), and it also seems to be off, as the aperture dial does not seem to correspond exactly to the exact aperture. On the bottom end of the scale, the lens is at fully open between the 4.5 and 5.6 markings (at about 4.8). The lens does not seem to visibly stop down until about 6.8. On the top, the scale is completely off. The wide open (4.5) indication shows clearly visible iris blades, and the maximum selectable aperture on the index is 32 (it goes to 45).

It seems simple enough to just unscrew it and flip it over and set wide open to full aperture, but I wanted to check with someone who knows before I do it. Any advice? I would just return it to KEH and let them deal with it, but I live in Iceland, and I paid a lot to get the lens here and already paid a lot in taxes for the lens. It is a huge pain to return it, as I will need to get in touch with customs to get my VAT refunded etc etc. I am hoping to fix this myself, or if that is not possible, just have someone local have a look. Problem is that there are not too many people left here that work in camera repair.

Is this a simple fix, or should I leave it to an expert? I shoot mostly with black and white film, so at this point, I am more concerned with just getting a working lens than with accuracy to 1/6th of a stop...right now I cannot use the lens at all unless I flip it upside down, as the aperture lever jams on the linhof type board. (The camera is an Ebony SV45ti.)
Thanks! I am attaching a picture.

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[Dan Fromm]

Please explain more fully.

Is the lens a 90/4.5 or a 90/6.8?


I shoot mostly with black and white film, so at this point, I am more concerned with just getting a working lens than with accuracy to 1/6th of a stop.

You should be able to put a spacer between the back of the shutter and the board.

If I'm not mistaken, the aperture scale is a piece of metal tape that's held to the shutter barrel by two screws. If so, figure out which lens you have and then check with Sinar, Rodenstock, whoever that means nowadays, and skgrimes about getting the right scale for your lens.

Eh? Wot? B/W film has broad exposure latitude, +/- 1/6 stop makes no practical difference.

[Bob Salomon]

What board are you trying to mount this on? Linhof does not make a recessed board for a 90 with a 1 size hole.
Your first move should be to contact the seller and find out if this is the original shutter or a remount.

[Mark Sawyer]

Have you tried actually measuring the aperture and calculating (focal length/aperture) whether it's giving you the correct f/stop value on the scale?

[Dan Fromm]

Mark, shouldn't the lens' barrel or trim ring be engraved with its name, rank and serial number? Sorry, name, focal length and maximum aperture?

[Mark Sawyer]

One would think, Dan. I'm guessing from the looks it's a Sinaron W 90mm f/4.5, but as the OP didn't say... Sinar screen-printed its info on the barrel, the other side of the barrel in the photo posted, I think.

[LabRat]

The quick check of the aperture scale would be that you know what the wide open f-stop and FL of the lens is (as marked on front ring of lens, so now you can use the formula Mark posted above, or you can set-up your camera facing a evenly illuminated wall, focus your camera to infinity, throw a focusing cloth over the back and take a digital meter and set the scale to match your wide open f-stop exposure reading on the center of GG from the back... Put a tape strip next to your aperture scale that you can mark on, and proceed metering the center of the GG... Stop down the iris slowly until there is one stop less light and put a dot on the tape strip where the pointer is, and proceed stopping down, marking every stop less, then look how your scale matches the marked scale... If you are careful, you should have a pretty good new scale to check against...

If this lens is too much trouble, throw it back... (Too many fish in the sea...)

Good luck!!!

Steve K

[Bob Salomon]

The quick check of the aperture scale would be that you know what the wide open f-stop and FL of the lens is (as marked on front ring of lens, so now you can use the formula Mark posted above, or you can set-up your camera facing a evenly illuminated wall, focus your camera to infinity, throw a focusing cloth over the back and take a digital meter and set the scale to match your wide open f-stop exposure reading on the center of GG from the back... Put a tape strip next to your aperture scale that you can mark on, and proceed metering the center of the GG... Stop down the iris slowly until there is one stop less light and put a dot on the tape strip where the pointer is, and proceed stopping down, marking every stop less, then look how your scale matches the marked scale... If you are careful, you should have a pretty good new scale to check against...

If this lens is too much trouble, throw it back... (Too many fish in the sea...)

Good luck!!!

Steve K

Steve, that metering technique won't work properly unless you determine the light loss from absorption from the gg and, if installed, the Fresnel. And, once you do determine that light loss you need to be sure that you have the Fresnel installed so the illumination is evenly spread across the measuring area.
Secondly, m out homes do not have a room large enough to focus at infinity. You would be better off just focusing on a distant power line against the sky.

[Bob Salomon]

One would think, Dan. I'm guessing from the looks it's a Sinaron W 90mm f/4.5, but as the OP didn't say... Sinar screen-printed its info on the barrel, the other side of the barrel in the photo posted, I think.

It is actually the Rodenstock 90mm 4.5, older version before the green stripe,with Sinar's name on it.

Since Iceland belongs to the EEA can't you send it back to Germany for service at the Rodenstock factory. Switzerland is not a member nation but Sinar is owned by Leica in Germany so they might also be able to help you.

[LabRat]

No Bob, we are not trying to measure for an exposure, but simply trying to measure the difference in brightness on the center of the GG as the lens is stopped down for a test... If the test reading is on-axis, and the meter is at a constant position, it will see the reduction of exposure as the lens is stopped down, so OK for a general test...

The infinity focus part is just about having the lens to film plane distance where there will be no bellows extension factors involved, to not throw the test readings off...

Hope this explains...

Steve K

[Pere Casals]

setting the aperture index on a 4x5 lens
[/ATTACH]

I can tell how I checked the same.

First I carefully spot metered a grey card with a Nikon F5 with 50mm 1.8D.

Then I removed the 50mm and I placed the F5 in the back of a view camera (Norma) with a DIY graflock to F Mount adapter,

like that 154147


Then I focused the view camera with the lens I had to check at infinite (to get nominal bellows extension) looking through the F5 viewfinder.

Then I pointed to the grey card with the view camera (without moving focus) and metered again. So I metered TTL both times.


We can guess that the Nikon 50mm f/1.8D (5 groups) has the same transmission than a multicoated LF lens (4 groups).

The SLR 50mm has an additional group, this is 2 additional air-glass surfaces so we can guess that the nikon 50mm 1.8D has 0.995x0.995 = 0.99 , this is the 99% of the transmitance performance of the LF lens, so the same in practice, as a full stop is 50%.


In fact the metering I got with the F5+Nikon 50mm matched pretty exactly the one that I had with F5 on the back of the view camera with LF lens focused at infinite. Note that if the view camera is not focused at infinite this won't work.

Of course you can also use a DSLR for that...

Regards.

[Steve Goldstein]

Years ago I had a shutter come back after a CLA by a very reputable firm with the aperture control lever mounted 180 degrees off. Could this be your problem? It's held by two very tiny screws, and the "repair" took less time to do than to type this.

[LabRat]

Oh, and did I mention my test is to be done outdoors on a brightly lit wall so there is a fairly bright GG that you can still take a reading on as the aperture is stopped down???
(Sorry for the omission!!!)

I use a digital spotmeter pressed against the GG with the spot circle just touching the center X lines and stop down from there... I have made some pretty OK scales for lenses that had no scale, that film tested quite well...

I have also home made a Nikon 35mm mount insert for the film plane that fits in the Graflok tabs (like Pere has) that I use for very close macro, and meter using a Nikon FE camera (that has an extended metering range), but don't forget to subtract the extra distance from the GG/film plane of the adapter, to the 35mm film plane + metering (esp with shorter lenses) when computing bellows draw... (Unless you are rolling the rear standard inward so the 35mm focus is at the same plane where the GG was...)

Steve K

[StuartR]

Hello all, thank you for all the help! I am sorry I did not respond earlier. It was night here and I did not get any notifications!
I am actually leaning towards Steven's explanation as being the right one, but I will call KEH to sort it out.

I am also sorry for the ambiguity. It is a Sinaron W 90mm f/4.5 in a Copal 1 shutter. It came from KEH in Ex+ condition, and they list all their gear as being inspected and tested. Indeed, the condition of the lens is very good, and the shutter seems to fire just fine, and the iris itself does not have any problems in moving.
That said, the aperture index lever is on the bottom of the lens, and the position does not seem correct. I will try to show a photo or two of the problem. The photos are of the moment when the iris first begins to cover the lens. So this is literally wide open...I would normally expect that since this is a 4.5 lens, the iris would begin covering part of the lens immediately after you stop down further than that. So if you choose 5.6 for example, the iris would cover more of the lens than at 4.5. Right now the iris does not cover any of the lens at all until about f/8. The question at this point is can I fix this myself, or does it need to be sent for repair. Again, living in Iceland makes it very inconvenient to return the lens. The return shipping will cost me at least 50 dollars, and I will have to go through a lengthy process of obtaining a refund from the customs office, which might take weeks or months. Seeing as the lens appears to be otherwise in good condition, I would rather just try to fix it.

P.S. I put the lens on a Sinar board just to test to see what the angle of view and vignetting looked like on my studio monorail, my normal use for this would be on a Linhof board in an Ebony.

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[StuartR]

Eh? Wot? B/W film has broad exposure latitude, +/- 1/6 stop makes no practical difference.

I am sorry Dan, I was not clear. I meant that +/- 1/6th would not be important to me. I just want a lens that I can trust to within about 1/2 of a stop.

As for the jamming, the lever moves smoothly on the board, but not when mounted on the camera. The lever moves past the bottom edge of the Linhof type board, and it rubs against the front of the camera. I would rather the lever was on the top of the lens anyway, like every other large format lens I use.

[Pere Casals]

the extra distance from the GG/film plane of the adapter.... ...when computing bellows draw...

Steve K


For bellows compensation... a tip I use when metering with a SLR in the back of the view camera: With the SLR in the the back I focus to the subject by using the viewfinder and I use the SLR as a spot meter,that reading will need no bellows compensation when I place the GG in place and I focus again at the subject, as when I focus with the GG I'm to move it just the "the extra distance from the GG/film plane of the adapter, to the 35mm film plane".

As the reading with SLR was made TTL and the subject in focus the reading can be used directly without any correction.

Even in the case a filter is used it is possible to evalute the resulting contrast of the scene, if a filter is used to darken sky, for example, and directly using those readings. The F5 (and modern DSLR) has the advantage of having a RGB class photometer, problem is weight.

What I like of having a DSLR to help the Norma is that one can make a test shot and see the histograms, for Velvia it is also useful to see histogram for each channel, and to evaluate suitable manual color correction when color temp drops.

It is very funny to see some LF photographers with a D810 photometer metering for a firewood camera :) (I use a consumer one)

[StuartR]

It is actually the Rodenstock 90mm 4.5, older version before the green stripe,with Sinar's name on it.

Since Iceland belongs to the EEA can't you send it back to Germany for service at the Rodenstock factory. Switzerland is not a member nation but Sinar is owned by Leica in Germany so they might also be able to help you.

Hi Bob, thanks for the help. Iceland is in the EEA, but not the EU. Unfortunately this means that I would have to pay VAT on the repair and deal with customs each way. The minimum cost to do this would likely be 400-500 dollars (shipping both ways, service and taxes), which is nearly as much as I paid for the lens.

[Bob Salomon]

Hi Bob, thanks for the help. Iceland is in the EEA, but not the EU. Unfortunately this means that I would have to pay VAT on the repair and deal with customs each way. The minimum cost to do this would likely be 400-500 dollars (shipping both ways, service and taxes), which is nearly as much as I paid for the lens.

Germany does not collect VAT on items made in the EU that are sent into the EU and that will be sent back out of the EU after repair. Contact the German Consulate for the correct details and paper work. We did this from the U.S. On a normal basis.

[StuartR]

Hi Bob, it is not the Germans I am worried about. I will pay an additional 24% VAT on the total FOB worth of the repair (including shipping) and I also have to file paperwork with Icelandic customs that costs about 30 dollars to prove that I sent the item out for repair. Please believe me that I know what I am talking about in this regard. I am a professional photographer and have dealt with living here and arranging repairs of gear to Germany and the US. I was hoping of people could just look at the pictures and read what I wrote and see if it is indeed wrong, and if so, if it is something I can easily fix. Thank you!

[Dan Fromm]

Thanks for the images. Image 1 looks quite normal, in image 2 the scale is on upside down and backwards. Undo the two screws that hold it to the shutter barrel, turn the scale right side up and replace, replace the screws.

[interneg]

This is what a Copal 1 should look like - http://www.schneiderkreuznach.com/uploads/pics/Verschluss_co_1_02.jpg

It looks a lot like post #12 is correct.

[StuartR]

Thank you everyone, and especially Steven and interneg. What you were describing seemed to be the issue to me, so I just took a tiny screwdriver and unscrewed the aperture lever and flipped it over, and sure enough, everything lined up perfectly. The lever is in the right place, and the iris seems to correspond very closely to numbers (so it is wide open at 4.5 and then starts to block the light as soon as you stop down further). Thanks again, and I am sorry to make things unclear...I am sure you could have all easily diagnosed this if it was right in front of you!