Pentax 645 taking 20+ photos

geggerz · 07-01-2019, 06:51 AM

I’ve shot 5 rolls of 120 film, so far only 2 have come out fine. Those two I was able to take the standard amount of photos for a 120 (I think 16?). The other 3 I haven’t taken to be developed, but I’ve been able to take 20-30 (or more) shots on them somehow. Does anyone know why the camera might be doing this? Every time I open the camera up after 16 shots, the roll is still there and a frame is exposed (also I have a feeling this might have exposed all the shots, but that’s besides the point and I’m prepared for the heartbreak).

Does anyone know how this can be fixed or if it can be? Or maybe it’s a camera setting? Any help is much appreciated!

pschlute · 07-01-2019, 07:23 AM

Sounds like the film is not advancing. Sacrifice a roll of film (or use a used one) and pull it out of the roll. Make some marks on it. The put it in the camera and snap away. Open it up and test what's happening.

**babywriter** · 07-01-2019, 06:35 PM

It might also be a faulty film cartridge. I had one that advanced film in semi-random increments. Gave me some great overlapping double exposures.

LaHo · 07-05-2019, 06:36 AM

Hi Geghani,

There is no setting in the camera for the number of frames. The number of frames is determined by the film back. There is one marked 220 for 220 film. This takes 30 frames on the Pentax 645 (16 frames on the 645N and 645N II). And there is one marked 120 for 120 film which takes 15 frames (16 on the 645N and 645N II), When the camera reaches the end of the film, you will hear it winding on to the end of the film.

I you happen to use 120 film in the 220 film back, the automatic advance will just go on past 15 (or 16).

It sounds as if you used a 120 film back for the first two rolls and a 220 film back for the next three rolls. That would account for what you have experienced.

BTW, as 220 film is rare these days, you can convert a 220 film back to 120 by removing a small plastic piece between the two metal spool hinges and turn it around. It is held in place by two small cross head screws. On 220 film backs it is mounted with a blunt end facing outwards, and on the 120 film backs it is mounted with a pointed end facing outwards. That - and the designation 120 or 220 - is the only difference between the 120 and 220 film backs, as far as I know. The pressure plate is the same.

I have converted several 220 film backs this way and used them with success on my Pentax 645N cameras.

**mnovikov** · 02-08-2020, 08:32 PM

Originally posted by LaHo

Hi Geghani,

There is no setting in the camera for the number of frames. The number of frames is determined by the film back. There is one marked 220 for 220 film. This takes 30 frames on the Pentax 645 (16 frames on the 645N and 645N II). And there is one marked 120 for 120 film which takes 15 frames (16 on the 645N and 645N II), When the camera reaches the end of the film, you will hear it winding on to the end of the film.

I you happen to use 120 film in the 220 film back, the automatic advance will just go on past 15 (or 16).

It sounds as if you used a 120 film back for the first two rolls and a 220 film back for the next three rolls. That would account for what you have experienced.

BTW, as 220 film is rare these days, you can convert a 220 film back to 120 by removing a small plastic piece between the two metal spool hinges and turn it around. It is held in place by two small cross head screws. On 220 film backs it is mounted with a blunt end facing outwards, and on the 120 film backs it is mounted with a pointed end facing outwards. That - and the designation 120 or 220 - is the only difference between the 120 and 220 film backs, as far as I know. The pressure plate is the same.

I have converted several 220 film backs this way and used them with success on my Pentax 645N cameras.

Thank you for th er idea of 120/220 back conversion!

07-01-2019, 06:51 AM	#1
geggerz New Member Join Date: Jul 2019 Posts: 1	Pentax 645 taking 20+ photos I’ve shot 5 rolls of 120 film, so far only 2 have come out fine. Those two I was able to take the standard amount of photos for a 120 (I think 16?). The other 3 I haven’t taken to be developed, but I’ve been able to take 20-30 (or more) shots on them somehow. Does anyone know why the camera might be doing this? Every time I open the camera up after 16 shots, the roll is still there and a frame is exposed (also I have a feeling this might have exposed all the shots, but that’s besides the point and I’m prepared for the heartbreak). Does anyone know how this can be fixed or if it can be? Or maybe it’s a camera setting? Any help is much appreciated!

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07-01-2019, 07:23 AM	#2
pschlute Moderator Loyal Site Supporter Join Date: Mar 2007 Location: Surrey, UK Photos: Gallery Posts: 8,211	Sounds like the film is not advancing. Sacrifice a roll of film (or use a used one) and pull it out of the roll. Make some marks on it. The put it in the camera and snap away. Open it up and test what's happening.

07-01-2019, 06:35 PM	#3
babywriter Site Supporter Join Date: Jan 2016 Location: central Iowa Photos: Gallery Posts: 969	It might also be a faulty film cartridge. I had one that advanced film in semi-random increments. Gave me some great overlapping double exposures.

07-05-2019, 06:36 AM	#4
LaHo Pentaxian Join Date: Mar 2007 Location: Greater Copenhagen Area Photos: Gallery \| Albums Posts: 430	Hi Geghani, There is no setting in the camera for the number of frames. The number of frames is determined by the film back. There is one marked 220 for 220 film. This takes 30 frames on the Pentax 645 (16 frames on the 645N and 645N II). And there is one marked 120 for 120 film which takes 15 frames (16 on the 645N and 645N II), When the camera reaches the end of the film, you will hear it winding on to the end of the film. I you happen to use 120 film in the 220 film back, the automatic advance will just go on past 15 (or 16). It sounds as if you used a 120 film back for the first two rolls and a 220 film back for the next three rolls. That would account for what you have experienced. BTW, as 220 film is rare these days, you can convert a 220 film back to 120 by removing a small plastic piece between the two metal spool hinges and turn it around. It is held in place by two small cross head screws. On 220 film backs it is mounted with a blunt end facing outwards, and on the 120 film backs it is mounted with a pointed end facing outwards. That - and the designation 120 or 220 - is the only difference between the 120 and 220 film backs, as far as I know. The pressure plate is the same. I have converted several 220 film backs this way and used them with success on my Pentax 645N cameras.

02-08-2020, 08:32 PM	#5
mnovikov Loyal Site Supporter Join Date: Aug 2009 Posts: 37	Originally posted by LaHo Hi Geghani, There is no setting in the camera for the number of frames. The number of frames is determined by the film back. There is one marked 220 for 220 film. This takes 30 frames on the Pentax 645 (16 frames on the 645N and 645N II). And there is one marked 120 for 120 film which takes 15 frames (16 on the 645N and 645N II), When the camera reaches the end of the film, you will hear it winding on to the end of the film. I you happen to use 120 film in the 220 film back, the automatic advance will just go on past 15 (or 16). It sounds as if you used a 120 film back for the first two rolls and a 220 film back for the next three rolls. That would account for what you have experienced. BTW, as 220 film is rare these days, you can convert a 220 film back to 120 by removing a small plastic piece between the two metal spool hinges and turn it around. It is held in place by two small cross head screws. On 220 film backs it is mounted with a blunt end facing outwards, and on the 120 film backs it is mounted with a pointed end facing outwards. That - and the designation 120 or 220 - is the only difference between the 120 and 220 film backs, as far as I know. The pressure plate is the same. I have converted several 220 film backs this way and used them with success on my Pentax 645N cameras. Thank you for th er idea of 120/220 back conversion!