Do you adjust your aperture?

malcao · Sep 14, 2009

I'm aware of that the shutter speed isn't exact but how about the aperture? It never crossed my mind until I bought my second Schneider 360mm (400 looks like new, couldn't let it pass
When comparing them I notice that they differ by about 1/3 stop.
Anyone had any thoughts about this and do you adjust your aperture?

EASmithV · Sep 16, 2009

Is it possible that while maintaining the same overall appearance, there was a slight modification in the design and the aperture was changed? The only thing I can think of is to stick a flat art incident meter in the back of your view camera, and use it to re-mark your f stop markings. Alternatively, it's possible that the f stop scale can be loosened with a set screw and then rotated to be calibrated, but I'm, not familiar with your particular lens.

PS; I'm surprised that no one else has commented on this yet... Unusual for APUG...

Ian Grant · Sep 16, 2009

Well an Uncoated, Single coated and Multi-coated lens design of the same aperture will pass differing amounts of light.

In practice there's very little difference between my single (& well) coated 1950's 150mm T CZJ Tessar and my Multi-coated Schneider's & Rodenstock's. So there's no need to make any adjustment.

Ian

bsdunek · Sep 16, 2009

This comes under knowing your equipment. If you are in a situation where exposure is very critical, you know the differences in your lenses and can compensate accordingly. I have an old Gossen light meter that reads about 1/2 stop high. Otherwise it is fine, so I just remember that.

ic-racer · Sep 16, 2009

Your aperture scale may not be the correct one for the lens. Making aperture scales and /or calibrating them is certainly somethig LF photographers are interested in. There are many threads on this topic.

Ed Sukach · Sep 16, 2009

It may be of use to rememebger that the exposure is determined by the ACTUAL f/stop, where f/= distance to film plane / aperture diameter. The lens, accompanied by the aperture, is normally extended out beyond the "Infinity Focal Length" when taking anything closer than "infinity focus" - most noticable in "close-up" photography. Many "bellows equiped cameras wil have an exposure compensation scale linked to the bellows.
Most lenses have the apertures marked for infinity focal length, and will automatically underexpose.

Another photographic anomally, "inaccurate f/stops", worthy of consideration.

BrianShaw · Sep 16, 2009

I have never been bothered by the minor exposure differences except those of greater magnitude from poor shutter speed performance. So, no, I have never even thought of adjusting (calibrating) aperture.

John Koehrer · Sep 16, 2009

I'm not sure you can adjust the aperture. The blades are fixed to the blade operating ring & that's it.
You might be able to fudge with the maximum aperture but it wouldn't have any effect on the rest of them.
Grimes may be able to test the lens & make you a new f-stop plate for $$$.

Mike1234 · Sep 16, 2009

I'm just repeating others here but... if need be you could make a new aperture scale calibrated to the lens (or have one made), or you could tape a paper one over the existing scale, or you could just keep a chart of corrections and adjust by that. As others have stated, the scale "should" be very accurate unless there's something awry.

malcao · Sep 29, 2009

On the 360/6.8 Symmar-S you can adjust the aperture at both the start point and end point. I changed one of the lenses so they appear to be more or less the same. Before you could just notice the aperture blades at 6.8 if you move the stop screw one pinhole you will have a full opening and go past 6.8 on the aperture scale, I'm not sure if this mean 5.6 anyway it's nice to have the option to shoot wide open.

Do you adjust your aperture?

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