Can a Copal shutter be adjusted for accurate highest speed? 1/500, 1/400 ?

[Dan Fromm]

Not to be a complete idiot, but why don't you use faster film or dispense with the leaf shutter and use a camera with a focal plane shutter such as a Speed Graphic?

[Pere Casals]

For aerial photography.

OK, most of the shutters don't reach the marked top speed, at least none of those I have.

In fact manufacturers specified that speed accuracy is +/-30%, so if a new shutter had a mark that said 1/400 but actually it was 1/280 then it fulfilled specs, so in theory no warranty claim had force. A common situation is that the max speed uses that margin in the low speed side. At the end 1/500 speed usage is not very common for LF, then LF photographers IMHO never cared.

So best way can be measuring well what what actual speed it has, and if it is repetitive, and adjusting aperture for the real speed you have. Mechanical shutters are not as precise as electronic ones, still are precise enough for potography work.

The good news is that even there is a difference from marked speed the exposure time is very repetitive, it can change if it is stored long time and not doing regular CLAs.

[LabRat]

Not to be a complete idiot, but why don't you use faster film or dispense with the leaf shutter and use a camera with a focal plane shutter such as a Speed Graphic?

One downside with a LF FP shutter would be that with fast low altitude firing, the slightly slow curtain movement might cause a speed distortion effect if flying fast and low...

FWIW, my take on it is if not using a dedicated aerial camera designed with a rugged, fast powerful leaf shutter, it might be better just to use a smaller format camera with a large film or chip load, with high speeds that are a true speed, and even smaller cameras with a top shutter speed of 1/2000, 1/4000, 1/8000 etc...

I suggest again, an aerial photographer probably has MANY old film cameras they won't use now due to digital imaging, and probably has one you can have for little or nothing, so seek this out first...

Steve K

[Pere Casals]

No noticeable speed distorsion with common (non military) aerial photography speeds, if 100 knots this is 185km/h this is 51m/s, so at 1/500 the ground will move 4 inches during exposure.

If 200 knots (!) then ground will move 8 inches. Nothing noticeable in an aerial scene.

[Dan Fromm]

One downside with a LF FP shutter would be that with fast low altitude firing, the slightly slow curtain movement might cause a speed distortion effect if flying fast and low...

FWIW, my take on it is if not using a dedicated aerial camera designed with a rugged, fast powerful leaf shutter, it might be better just to use a smaller format camera with a large film or chip load, with high speeds that are a true speed, and even smaller cameras with a top shutter speed of 1/2000, 1/4000, 1/8000 etc...

I suggest again, an aerial photographer probably has MANY old film cameras they won't use now due to digital imaging, and probably has one you can have for little or nothing, so seek this out first...

Steve K

Y'know, there are many aerial cameras with focal plane shutters.

[LabRat]

Y'know, there are many aerial cameras with focal plane shutters.

Sure, but our rubber cloth versions are much less tension... The leaf + FP military aerial cameras I have messed with have powerful, metal bladed leaf or FP shutters that can snip or slice off your finger, if that finger was in the wrong place at the right time... :-0

Hope the new year is great for you and yours!!!!

Steve K

[Dan Fromm]

Steve, Speed Graphics' faster shutter speeds are in the range of aerial cameras' focal plane shutters' speeds. The only aerial cameras with metal FP shutters that come to mind at the moment are the Williamson F.134 and its successors the AGI F.139 and Agiflite. These are essentially cine cameras, have rotating sector shutters. I'm sure I missed some, correct away. You might want to count OMERA and S.F.O.M. aerial cameras too, these beasts have bizarre metal venetian blind shutters, change speeds by changing the shutters.

What's more interesting is why the OP is so fixated on lenses in leaf shutters. He has a problem that seems to have a simple and relatively inexpensive solution, but he ignores it.

[Bob Salomon]

Steve, Speed Graphics' faster shutter speeds are in the range of aerial cameras' focal plane shutters' speeds. The only aerial cameras with metal FP shutters that come to mind at the moment are the Williamson F.134 and its successors the AGI F.139 and Agiflite. These are essentially cine cameras, have rotating sector shutters. I'm sure I missed some, correct away. You might want to count OMERA and S.F.O.M. aerial cameras too, these beasts have bizarre metal venetian blind shutters, change speeds by changing the shutters.

What's more interesting is why the OP is so fixated on lenses in leaf shutters. He has a problem that seems to have a simple and relatively inexpensive solution, but he ignores it.

Not a metal focal plane shutter but instead a metal rotating guilitine shutter with speeds to 1/6000. The Linhof Aerotronica. Uses 100’ 70mm rolls, so not a 45. But much larger then the 45 Linhof Aero Technika EL with the 5” roll vacuum back.

[LabRat]

Steve, Speed Graphics' faster shutter speeds are in the range of aerial cameras' focal plane shutters' speeds. The only aerial cameras with metal FP shutters that come to mind at the moment are the Williamson F.134 and its successors the AGI F.139 and Agiflite. These are essentially cine cameras, have rotating sector shutters. I'm sure I missed some, correct away. You might want to count OMERA and S.F.O.M. aerial cameras too, these beasts have bizarre metal venetian blind shutters, change speeds by changing the shutters.

What's more interesting is why the OP is so fixated on lenses in leaf shutters. He has a problem that seems to have a simple and relatively inexpensive solution, but he ignores it.

I can't remember which ones, but I did salvage titanium FP shutters from outdoor junkpile large cameras years ago (for parts + lenses)... Maybe they were capping shutters???

Maybe it was also a little Maurer 70MM with one...

Still plenty of old aerial cameras out there, but I'd prefer something with a roll film load or digi, maybe motor drive, auto exposure, easy to see through & handle, or to fulfill my William Garnett fantasy, war surplus... It would also be cool to have a with a B-25 or LearJet with a camera bay, but short of that (for a few shots), a wooden box with a graflok back on one side, and a lens on the other if I decided to shoot just one or a couple of sheets over a site...

I still say to hit up aerial photographers... They had awesome gear cabinets I have seen, and know they won't be used by them again...

HNY

Steve K

[pchaplo]

Good idea. I will ask Carol Flutot and I also found another shop S.K. Grimes.

To me, it seems that Copal shutters are optimized for the lower speeds. It reasonable that something could be done to optimize the shutter to consistently provide the marked high speed as in 1/500 sec for Copal 1. From what I understand, that would typically take a 1/3-1/2 stop increase in performance. That would be useful to me.

Have you asked Carol Flutot?