SL66 + 150/f4 synchro compur + flash = underexposure

[Bessa-ist-das]

Hi,

this is a tricky question and I've talked to my local camera repairman about it and he couldn't locate the problem:

I've recently made some photos using a studio flash. For some test shots upfront I used my Nikon dslr to get lighting right etc.

ISO was set to 400 on the DSLR, exposure metered f11 at 1/250s (with external flash meter). I shot a couple of frames on the DSLR and was pleased with the result on the display on my Nikon (histogram et al).

Then I changed cameras, using my SL66 Rollei MF SLR with a 150mm synchro compur Zeiss lens.

I loaded a roll of Neopan 400, set the aperture at f11, exposure time on the camera body to "B", on the lens (leaf shutter) to 1/250th, set the flash mode to "X" (on the lens) attached the sync cable to the X contact on the lens, cocked both camera shutter and leaf shutter on the lens and took the shot. The flash fired and everything seemed fine. So I shot the whole roll without much further ado.

I expected to have pretty much identical results in terms of exposure on film and on digital as the setup hadn't changed except for the camera used, however with identical exposure parameters. But the shots on film are hopelessly underexposed (must be at least 3 stops).

I took the camera to my local repair man to have the issue checked as I expected the shutter and flash contact to be out of sync on the Rollei or the lens. The guy at the camera repair shop checked lens and camera and said that the flash falls correctly in sync with the open shutter. He showed me how the flash light was visible through the back of the body when fired without a magazine attached.

So, as you can imagine, I'm quite confused... anyone ever experienced something like that? Any suggestions/solutions?

Hope the explanation is more or less clear...

Thanks for your time and help!
Wolfgang

 

[FallisPhoto]

The success of setting exposures with a small format digital camera for a medium format film camera is going to depend a whole lot on how you have the digital camera set up, the white balance setting, what filters are in the digital camera (there is an IR shield in there for sure), crop factor and etcetera. The digital camera's meter compensates for all this. Also, no two different cameras meter the same. For example, Minolta's cameras are set to recommend exposures based on 13% gray while Rolleis are based on, I think, 18% gray. The phrase apples and oranges comes to mind. You really need a handheld meter. Gossen and Sekonic are two popular brands that are reliable and won't cost an arm and a leg.

 

[john_s]

Are you certain that the processing of the Neopan was ok?

Your procedure looks ok to me. I notice that you used a flash meter for the digital test shots. Did you use the flash meter for the SL66 setup? I wonder if something changed in the flash output when going from one camera to the other.

 

[FallisPhoto]

Are you certain that the processing of the Neopan was ok?

Your procedure looks ok to me. I notice that you used a flash meter for the digital test shots. Did you use the flash meter for the SL66 setup? I wonder if something changed in the flash output when going from one camera to the other.

Oops! I missed that he used a flash meter. Could it be that the SL66 is overdue for a CLA? They made those as far back as 1966 didn't they?

 

[FallisPhoto]

Hi,

this is a tricky question and I've talked to my local camera repairman about it and he couldn't locate the problem:

I've recently made some photos using a studio flash. For some test shots upfront I used my Nikon dslr to get lighting right etc.

ISO was set to 400 on the DSLR, exposure metered f11 at 1/250s (with external flash meter). I shot a couple of frames on the DSLR and was pleased with the result on the display on my Nikon (histogram et al).

Then I changed cameras, using my SL66 Rollei MF SLR with a 150mm synchro compur Zeiss lens.

I loaded a roll of Neopan 400, set the aperture at f11, exposure time on the camera body to "B", on the lens (leaf shutter) to 1/250th, set the flash mode to "X" (on the lens) attached the sync cable to the X contact on the lens, cocked both camera shutter and leaf shutter on the lens and took the shot. The flash fired and everything seemed fine. So I shot the whole roll without much further ado.

I expected to have pretty much identical results in terms of exposure on film and on digital as the setup hadn't changed except for the camera used, however with identical exposure parameters. But the shots on film are hopelessly underexposed (must be at least 3 stops).

I took the camera to my local repair man to have the issue checked as I expected the shutter and flash contact to be out of sync on the Rollei or the lens. The guy at the camera repair shop checked lens and camera and said that the flash falls correctly in sync with the open shutter. He showed me how the flash light was visible through the back of the body when fired without a magazine attached.

So, as you can imagine, I'm quite confused... anyone ever experienced something like that? Any suggestions/solutions?

Hope the explanation is more or less clear...

Thanks for your time and help!
Wolfgang

How long has it been since you CLAd the SL66?

 

[john_s]

How long has it been since you CLAd the SL66?

If the camera were misfunctioning due to lack of CLA, i think that the only symptoms would be inaccurate shutter speed or failure of X synch. Since the OP is using flash and as far as I can gather the whole frame is exposed, it seems to me that the shutter is good enough for this task. (Both shutters, that is). In my experience, an SL66 that needs adjustment shows uneven exposure across the frame due to focal plane shutter curtains not properly synnchronised. That is not happening in this case.

 

[FallisPhoto]

...or failure of X synch.

Exactly. If the shutter is hanging up until after the flash goes off, it would explain why they were underexposed.

 

[john_s]

The guy in the camera shop said that the x-synch appeared to be ok. My guess is that if the x-synch were inaccurate, the result would be no exposure, since the shutter speed is quite fast and the flash duration would also be very fast. It would be amazing if the shutter could cut the flash by two or three stops since the timing is extremely short. If it were actually happening, I would expect a lot of unevenness across the frame.

Could there be a problem with the aperture setting of the lens? I have an SL66 150mm lens (not the internal shutter one) where the aperture mechanism has become faulty. It gives a couple of stops less than indicated.

I would play around with the flash meter with the flash on the SL66. Maybe try the shot just using the focal plane shutter at 1/30 which is the max synch speed.

Does the lens give good results at f11 in daylight and normal metering?

 

[Al Kaplan]

We never had that problem when we used Polaroid test shots.