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09-20-2016, 02:10 PM   #1
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P6x7, P67: one second minimum shutter speed a limitation?

I'm in the process of kicking the tires on an as-yet-hypothetical MF kit I'd kick around with here in the Southern Appalachia's. The P6x7 and P67 are at a much more reasonable price point for me than the 67ii--especially since I'm shooting off a tripod almost always--but I'm concerned whether their relatively "fast" lowest shutter speed is going to trip me up.


A quick pass through my EXIF data from my K5 tells me that when shooting a wide angle lens with a CPL, usually at f/11, my shutter speeds can drop down to near one second when I'm under a heavy canopy and/or shooting in the gloaming. If the rule of thumb is to stop down a couple of stops for MF to maintain comparable DOF, I could see my shutter speeds starting to edge below one second, assuming I did without the CPL on the medium format camera. (I'd also be running into reciprocity issues with, say, Velvia 50, but I'll cross that bridge when I come to it...)


I'm curious if this has been an issue for any of y'all in your shooting and if there's a better solution out there than Bulb mode and "one-Mississippi".

09-20-2016, 02:23 PM   #2
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I used to have a mechanical device used for long shutter speeds. It screwed into the shutter release like a cable release.

These days prontor is about all i see on ebay and it is more than $200 usually.
09-20-2016, 03:26 PM - 1 Like   #3
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QuoteOriginally posted by UncleVanya Quote
I used to have a mechanical device used for long shutter speeds. It screwed into the shutter release like a cable release.

These days prontor is about all i see on ebay and it is more than $200 usually.
Oh jiminy! I remember those. Sort of the hybrid love child of a mechanical parking meter timer and a cable release.
09-20-2016, 03:31 PM   #4
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Using the bulb setting has not really been a problem. It may take you a few shots to get used to timing it though. If you are used to hearing the 1 second shutter firing, it is fairly easy to extrapolate to 2, 3 and 4 seconds.

09-20-2016, 04:54 PM   #5
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Watch with seconds or cell phone on timer mode plus cable release is an easy fix.
09-20-2016, 05:00 PM   #6
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There's no limit, you can use a cable shutter release. And you can keep it open as long as you want or as long as the film your using allows you to.

One thing you have to keep in mind is the film reciprocity. You'll need to adjust your time exposure depending on how long you want the shutter open. Just search reciprocity table for the film you're using.

Last edited by Pablo Villegas; 09-21-2016 at 01:13 AM.
09-20-2016, 08:18 PM   #7
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1 Mississippi
2 Mississippi

The above poster makes a great point about reciprocity. 1 - 2 seconds is usually not an issue though. Check film data sheets. I think Ektar is 8 or 16 seconds (on mobile at the moment so can't check). The other thing to consider is colour shifts on longish exposures.
09-20-2016, 10:28 PM   #8
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CPL with wide angle lenses and landscapes (eg sky)? I have done a lot of long exposure work with my Pentax 67 but none with positive film. For negative film, it's not a problem counting out a few seconds. Longer and just use your watch. Close enough. And the longer the exposure, the less precise you have to be. You have a wide exposure latitude when shooting negative film.

Edit: FYI, with BW film and Fuji's 100 Acros, you don't have to worry about reciprocity effects. It doesn't have that problem. Fuji does say add an extra 1/2 stop of exposure after 120 second metered exposure but with the latitude of that film you won't notice if you didn't.


Last edited by tuco; 09-20-2016 at 10:35 PM.
09-20-2016, 11:10 PM   #9
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Reciprocity of RVP50 aside, the Bulb mode is the best for long exposures and is not a concern nor a problem for experienced users proficient with the 67 system.
I am frequently up to 15-25 seconds on Velvia 50, uncorrected (or how about a 7-hour exposure of star trails? Nope, I don't give a hoot for reciprocity, just the fun!).
The alternative to keeping Tv speeds up is to use another film besides Velvia, such as Provia 100F, pushed +1, or Provia 400X, as is or pushed +2 or Portra 160 (generous latitude) pushed +3 ~ +4. Films like Velvia 50 means you are confined to shooting with a tripod. At low speeds you will not achieve absolute sharpness with the P67 handheld because of the inertia of the shutter/mirror activation. Sure, a postcard print may look sharp, but enlarge it to 80cm across and you will see the image is much less than optimum. Ease into good habits early and the P67 will reward.
09-21-2016, 05:03 AM   #10
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QuoteOriginally posted by Silent Street Quote
At low speeds you will not achieve absolute sharpness with the P67 handheld because of the inertia of the shutter/mirror activation.

Thanks for the hand-holding, gents--looks to be doable, though I anticipate that exposures only slightly above one second might be hardest to judge correctly...it might be worth stopping down even more to get to a reasonable number of "Mississippi's."


Speaking of that "trebuchet" shutter, though--I've seen where some people actually "hand-hold" the camera body while it's on the tripod to help dampen vibrations...any other tips or tricks?
09-21-2016, 09:56 AM   #11
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Shutter vib is not a problem with lenses in the 35mm to 150mm range but beyond that, one has to be careful. Even lenses with a tripod mount will have problems with this. Also, be aware that the lenses' DOF scales are not as accurate as shown. One must focus a bit more toward infinity to attain the sharpness you want. There is a forum on this site specifically for this camera, here Heavy Pentax - for 6X7 format users - PentaxForums.com
09-21-2016, 10:14 AM   #12
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QuoteOriginally posted by desertscape Quote
One must focus a bit more toward infinity to attain the sharpness you want.

Excellent, thanks for the link--no doubt the accumulated "Kentucky Windage" expertise will make the learning curve not quite as steep!
09-21-2016, 12:23 PM   #13
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I don't know if the Pentax 67 has a mirror up option, but you should certainly use it, for longer exposures.
09-21-2016, 01:32 PM   #14
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QuoteOriginally posted by Pablo Villegas Quote
I don't know if the Pentax 67 has a mirror up option, but you should certainly use it, for longer exposures.
Just an FYI. Exposures over, say, 10 seconds why bother with MLU. The duration of any vibrations is so short compared to the length of the exposure you won't record any vibration. And in the case of 2 to 4 minute exposures which I encounter a lot ( hardly any 2 to 4 second shots) it absolutely doesn't matter if you use MLU.
09-21-2016, 02:00 PM   #15
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QuoteOriginally posted by tuco Quote
Exposures over, say, 10 seconds why bother with MLU

Pablo--I think the 67 and later versions of the 6x7 had MLU, so I think I'm good there.


Tuco-- that's a good point...and no doubt I'll come up with dead batteries at some point from using MLU and forgetting it!
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