First Large Format (Ignorance and Expense)

btaylor

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Like Greg Y says, much of this info is out there. When it's not or hard to find, $23 will do the job. They work, zeros with the push of a button, my measurements are repeatable. Would I depend on them in a professional environment? No. For occasional use with my photos endeavors? Yes.

Harbor Freight. Cheap calipers
 

btaylor

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Yea, I am speaking for myself- I assume you are speaking for DREW WILEY, yes?

Rear mounted filters work fine, regardless if that was part of the design. I agree, it is unwise to use them when they have grime, or are creased or scratched. I imagine that applies to any filter.
 

DREW WILEY

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I think you would find under a magnifier there is some actual image detail loss if you use even gels behind the lens. Any optical engineer would probably also tell you that. I've tested for it. And if you look at process lenses for the graphics industry, their filter slots are engineered for the symmetrical nodal point, not the rear; or front-mounted filters can also be used. A few odd lenses like really big teles might have a built-in rotating filter selection; but it's always at some engineered mid-point, never at the rear.

I realize that for decades certain photographers had that habit and never complained. But when you look at the end results compared to today's standards of lenses and sharpness, it's certainly off.
 

tih

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MTGseattle said:
I have 3 EL-Nikkor enlarging lenses that are supposed to be 39mm. My caliper measured them all differently.
Click to expand...

You cannot reliably measure thread diameters by applying calipers to the outside of the thread. For accurate, repeatable, measurements, special wires are placed in the thread grooves, and the calipers are used to measure across these. This way, you measure based on where the thread groove has a certain width, ignoring how deep it happens to be cut, and how high and pointy the top of it may be.
 

DREW WILEY

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Toy calipers, ignorance of correct technique, no difference. That's why I recommended just looking up the thread specs on the appropriate mfg tech sheet. Of course, once in awhile there is an internal evolution of even the same focal length from the same mfg which requires some caution with the specifics. But really odd lens threads are rare among name brand enlarging lenses. And for way less than the cost of even a Harbor Shipwreck caliper, one can simply buy a cheap step ring of the suspected size at the local camera store and test the fit.
 

grat

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tih said:
You cannot reliably measure thread diameters by applying calipers to the outside of the thread.
Click to expand...

You cannot precisely measure thread diameters by applying calipers to the outside of the thread (and I'd argue that you measure the inside diameter of the thread, but that's splitting hairs), but you can get a reasonable estimate. Knowing the precise thread diameter down to the last micron isn't really necessary, as there are "common" filter sizes-- if you measure the inner diameter of the threads on a lens and it comes up 64.2mm, you might want to check again, as 65mm filters aren't very common. But if it's 66.2mm, chances are, it's a 67mm filter.

Also, anecdotally, most of my lenses, the inner diameter of the thread is 0.8mm less than the filter size, implying a 0.4mm thread depth. So a 45.2mm measurement is a 46mm filter, a 54.2mm is a 55mm, etc..

As Drew says, step rings aren't that expensive-- and since I try to use the same filter size as much as possible (mostly I buy 67mm), I have a small collection of step-up rings, and they can be used to verify filter size.

And sometimes, look for the ⌀ symbol on the lens. Newer lenses are frequently marked.
 

MTGseattle

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The only reason I even got the calipers out of my drawer for the EL-Nikkors is due to different generations of the lenses. I have what I think is a most recent sample of the 50mm f2.8 (all black, metal content unknown) which has the appropriate data sheet in the box still. All of my numbers with my improper technique were close enough to 39mm that I didn't question things (as far as lens boards go).
I had never heard of the technique that @tih mentions above. I think that level of accuracy would be important if one were trying to mount lens cells into a shutter.
 

tih

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MTGseattle said:
I had never heard of the technique that @tih mentions above. I think that level of accuracy would be important if one were trying to mount lens cells into a shutter.
Click to expand...

It's used when you need the precision, like when you're cutting threads on a lathe, and you need them to come out exactly to spec. When I mentioned the technique here, it was really just to point out that measuring threads with calipers won't give you a precise result (and, as grat says, you have to deduce the nominal thread diameter from the approximate major or minor diameter you're measuring, anyway). So don't worry about the variations you saw - instances of the same thread size are going to vary in those measurements.

SK Grimes has some handy instructions here: https://skgrimes.com/services/how-to-measure-threads/
 

MTGseattle

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I'm not sure how much labor is involved on the coding side, but this site could use a "like" button for situations where a user replies with valid info for another user. "Like" would acknowledge that that the info has been read and appreciated without creating a whole new reply. I guess this does open the argument for a "dislike" button as well.

How far have we derailed the OP's thread now? Ha ha.
 

MattKing

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We have decided in the past that it is better not to have "like" buttons, but rather encourage people to manually post their reactions.
 

Mick Fagan

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MattKing said:
We have decided in the past that it is better not to have "like" buttons, but rather encourage people to manually post their reactions.
Click to expand...

Always wondered why, now I know.

Great idea and I'm sure it sometimes does generate written replies that add to the thread.
 

Donald Qualls

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Mick Fagan said:
it sometimes does generate written replies that add to the thread.
Click to expand...

Unfortunately, I think it also generates work for the mods sometimes, when folks are, um, less than tactful in posting their reactions...
 

koraks

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Donald Qualls said:
Unfortunately, I think it also generates work for the mods sometimes, when folks are, um, less than tactful in posting their reactions...
Click to expand...

Not too worried about that It comes with the territory, and if you break it down, it's only a tiny percentage of all posts that require intervention on our part.
 
OP
OP

John Patrick Garriga

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Hey y’all.
I’ve got some concern over a couple of my lenses. My 210mm seems to have issues with the shutter. Occasionally when firing on slower shutter speeds I can notice my shutter not firing at all or firing very quickly. Is there a way to fix this or do I need to send it back to KEH, or the manufacturer? We don’t have anybody that I know of in town who works on large format lenses.
I am borrowing a lens from someone and it has an “M” and an “X” setting on it. It doesn’t do anything I can notice and he doesn’t know what it does either. It’s a Komura 300mm if that matters.
 

Alan Edward Klein

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Well, the shutter could probably be replaced. It;s not made by Schneider however and you'd have to take it from another lens. But why should you incur the expense? Doesn't KEH warrant it?
 

GregY

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JP, dry fire your 210 at all the slow speeds and see if this is an occasional thing. The real answer is the shutter likely needs cleaning. If you just bought it..... see if KEH will service it. If it's a Copal shutter..... Copal is the manufacturer....Schneider made the lenses....not the shutters.
 

Sirius Glass

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Return it the KEH and they will repair or replace the lens. I bought a Hasselblad C 500mm lens from KEH that jammed the first time I fired it. KEH hand to completely disassemble the optics to get to the shutter and then reassemble and collimate the lens. KEH paid for all the shipping. If I had sent it to Hasselblad it would have cost over $750.
 

bdial

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Regarding the M and X settings on the Komura, as mentioned, that control is for setting flash synchronization with either a bulb flash (M) or electronic flash (X).
You won’t be able to tell the difference by just looking through the lens and firing the shutter without a flash attached.
The M setting delays the shutter action by a few milliseconds to allow time for a flash bulb to get to its full brightness. X allows the shutter to fire immediately.
If you aren’t using a flash, it doesn’t really matter which one is selected, though I’d leave it on X.

For your 210, as others have mentioned, your likely best course of action is to send it back to KEH, either as a warranty fix, or just a repair paid by you if you’ve had it longer than their warranty time. Giving it a “CLA” (clean, lube, and adjust) is relatively simple, and should be an easy thing for their repair department.
If it’s still covered by their guarantee, they may give you the option of exchanging with another (hopefully working) lens. If you aren’t in a hurry, I’d probably let them fix it. All shutters you don’t know the history of could probably use a CLA.
 
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Donald Qualls

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Here's an additional item to check on that 210 -- some leaf shutters will fire at 1/50 or 1/60 (give or take a stop) if "between speeds" on the slow shutter settings, because the pallet won't engage unless the speed cam is at one of the actual settings. Worth checking if this is what's happening before you get on the phone with KEH. If so, making sure you test fire the shutter before pulling the dark slide as part of your "dance" will save film if you happen to hit one of these "between speeds" settings.
 

JPD

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It's the other way around. The M setting doesn't delay the shutter action, but triggers the flash milliseconds before the shutter opens.
 

Donald Qualls

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JPD said:
It's the other way around. The M setting doesn't delay the shutter action, but triggers the flash milliseconds before the shutter opens.
Click to expand...

Right, and it does this by starting the actual shutter about 20 ms after the trip releases. Can't react before the action. Effects cannot precede their causes.
 
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