Help, Pentax SF1 Shutter curtain doesn't open.

newsjeff · 02-24-2016, 07:23 AM

I recently acquired a good condition SF1 SLR. Everything seems to work, except that in testing, the shutter curtain does not let in any light to the film. I have been working with it, and even on "bulb", the curtain moves, but is not opening to the film back, so no light is coming to the film chamber. The shutter does move the curtains up and down, but I can never see any light coming through. Is there any fix to this? Am I doing something wrong?

**Alex645** · 02-24-2016, 12:21 PM

I assume that your lens cap is off and the lens is set to the largest aperture (smallest number)? I also assume you can see that the mirror is rising out of the way with each actuation with the lens off from the front?

There are some cameras that the shutter curtain will not open when the back is open/off, such as my 645. But I don't think that is the case with the SF1 and it unfortunately sounds like the SF1 is not in "good condition". For some reason your front/first curtain or your rear/second curtain is not remaining open for the correct shutter speed.

Before giving up, I would run a roll of film through it, shooting methodically at all shutter speeds, and either shoot something with motion so IF it works you can see if the shutter speeds are approximately working, or leave the aperture around f/8 with an ISO 400 film in full sun and just change shutter speeds. If you can't develop it yourself, take it to a lab that won't charge for a bad roll, and ask them to "develop only". You'll probably just get blank shots, but hopefully you will see bracketed exposures and the issue is just that the SF1 is designed to not open the shutter with the back open.

Treker · 02-24-2016, 12:34 PM

I just had a look at mine, if the back is open it will only fire at 125th of a second. The best way to check operation is to set the time to man. 1 second, remove lens and fire the shutter, you should be able to easily see the pressure plate from the front.

newsjeff · 02-25-2016, 07:47 AM

Originally posted by Treker

I just had a look at mine, if the back is open it will only fire at 125th of a second. The best way to check operation is to set the time to man. 1 second, remove lens and fire the shutter, you should be able to easily see the pressure plate from the front.

I did set it to manual and bulb, and took off the lens and looked inside. I did not see the pressure plate, just the shutter leaves. I tried it with a test roll of exposed film and did not see the film exposed through the front either. The shutter sounds normal and the shutter looks like it moves normally up and down, but no light is coming through! I sure wish it could be a simple fix, but it probably is not. Not worth it to me to have it repaired. Otherwise everything on the camera seems to work as it should.

**Alex645** · 02-25-2016, 10:56 AM

If Treker says you can view the SF1 pressure plate from the front with the back closed and lens off, and you can't, the shutter is in need of repair.

I often have students who have bought or were given used FSLRs and were told it was in good condition, but soon discover light leaks, broken light meters, defective shutter curtains, etc. Most of the time, the previous owner stopped using the camera because of this problem, but never got it repaired, and now a relative gives or sells the camera thinking its in good condition because cosmetically it looks great, but they don't know anything about the camera. The true test is running a roll of film thru it and getting it developed.

Very common on craigslist, eBay, pawn shops, garage sales, inheritance, etc. Very rare at camera stores, keh.com, or the PF Marketplace.

02-24-2016, 07:23 AM	#1
newsjeff New Member Join Date: Sep 2009 Location: Texas Posts: 4	Help, Pentax SF1 Shutter curtain doesn't open. I recently acquired a good condition SF1 SLR. Everything seems to work, except that in testing, the shutter curtain does not let in any light to the film. I have been working with it, and even on "bulb", the curtain moves, but is not opening to the film back, so no light is coming to the film chamber. The shutter does move the curtains up and down, but I can never see any light coming through. Is there any fix to this? Am I doing something wrong?

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02-24-2016, 12:21 PM	#2
Alex645 Site Supporter Join Date: May 2015 Location: Kaneohe, HI Photos: Albums Posts: 3,526	I assume that your lens cap is off and the lens is set to the largest aperture (smallest number)? I also assume you can see that the mirror is rising out of the way with each actuation with the lens off from the front? There are some cameras that the shutter curtain will not open when the back is open/off, such as my 645. But I don't think that is the case with the SF1 and it unfortunately sounds like the SF1 is not in "good condition". For some reason your front/first curtain or your rear/second curtain is not remaining open for the correct shutter speed. Before giving up, I would run a roll of film through it, shooting methodically at all shutter speeds, and either shoot something with motion so IF it works you can see if the shutter speeds are approximately working, or leave the aperture around f/8 with an ISO 400 film in full sun and just change shutter speeds. If you can't develop it yourself, take it to a lab that won't charge for a bad roll, and ask them to "develop only". You'll probably just get blank shots, but hopefully you will see bracketed exposures and the issue is just that the SF1 is designed to not open the shutter with the back open.

02-24-2016, 12:34 PM	#3
Treker Junior Member Join Date: Feb 2010 Location: Wisconsin Posts: 44	I just had a look at mine, if the back is open it will only fire at 125th of a second. The best way to check operation is to set the time to man. 1 second, remove lens and fire the shutter, you should be able to easily see the pressure plate from the front.

02-25-2016, 07:47 AM	#4
newsjeff New Member Join Date: Sep 2009 Location: Texas Posts: 4 Original Poster	Originally posted by Treker I just had a look at mine, if the back is open it will only fire at 125th of a second. The best way to check operation is to set the time to man. 1 second, remove lens and fire the shutter, you should be able to easily see the pressure plate from the front. I did set it to manual and bulb, and took off the lens and looked inside. I did not see the pressure plate, just the shutter leaves. I tried it with a test roll of exposed film and did not see the film exposed through the front either. The shutter sounds normal and the shutter looks like it moves normally up and down, but no light is coming through! I sure wish it could be a simple fix, but it probably is not. Not worth it to me to have it repaired. Otherwise everything on the camera seems to work as it should.

02-25-2016, 10:56 AM	#5
Alex645 Site Supporter Join Date: May 2015 Location: Kaneohe, HI Photos: Albums Posts: 3,526	If Treker says you can view the SF1 pressure plate from the front with the back closed and lens off, and you can't, the shutter is in need of repair. I often have students who have bought or were given used FSLRs and were told it was in good condition, but soon discover light leaks, broken light meters, defective shutter curtains, etc. Most of the time, the previous owner stopped using the camera because of this problem, but never got it repaired, and now a relative gives or sells the camera thinking its in good condition because cosmetically it looks great, but they don't know anything about the camera. The true test is running a roll of film thru it and getting it developed. Very common on craigslist, eBay, pawn shops, garage sales, inheritance, etc. Very rare at camera stores, keh.com, or the PF Marketplace.