Buying a used 645 - What to look for?

**germar** · 05-29-2012, 05:04 AM

Hi,

I'm about to take the jump into a Pentax 645 body and two lenses, all from an owner that sounds like she took good care of the gear.

I've purchased a good bit of used equipment including some film bodies, but I thought I would ask those who know here if there are specific things I should be looking for when inspecting the 645. I know the ultimate test would be to run a roll of film through it, but I won't have the luxury. Any tips or troublespots I should look into? I'm hoping to find a nice "daily driver" that will allow me to play in medium format.

Thanks in advance for any advice.

germar

aurele · 05-29-2012, 05:38 AM

i never used 645 body, but i guess, do like every time you buy a used SLR : check that the mirror work, the lever, shoot on all speed (without film).

Check exterior marks or scratch and check if it could have damaged internal mechanism.

Open the back to be sur the curtain isn't damage.

I may miss something but that's the big part.

Nesster · 05-29-2012, 06:08 AM - **1 Like**

The 645 suffers from "over-helpful" automation; i.e. there's very little you can do with the shutter without the back + film in it.

I've put together some bits and pieces about the camera here:
Pentax 645 guide - Modern Photo Test 1985 - lens resolution

the main posting is a repeat of the review I wrote here at pentaxforums:
Pentax 645 - 645 Medium Format - Pentax Camera Reviews and Specifications

**germar** · 05-29-2012, 11:50 AM

Thanks guys. I've read your excellent resources, Nesster. I'm lead to believe this camera has been taken care of and hardly been used the past handful of years. I'll check the battery compartment for corrosion and make sure there's no overt signs of neglect. Can you "dry fire" the 645's shutter when the back is off? I know it will be 1/1000 but that would be better than nothing.

Again, thank you.

germar

Smolk · 05-31-2012, 10:04 AM

On the 645, the diopter ring can actually be a bit loose which means you need to adjust it when you use the camera. Not a deal breaker but nice when it's in proper order.

unixrevolution · 05-31-2012, 10:41 AM

Originally posted by germar

Thanks guys. I've read your excellent resources, Nesster. I'm lead to believe this camera has been taken care of and hardly been used the past handful of years. I'll check the battery compartment for corrosion and make sure there's no overt signs of neglect. Can you "dry fire" the 645's shutter when the back is off? I know it will be 1/1000 but that would be better than nothing.

Again, thank you.

germar

I actually got a 645 on the cheap cause the pawn shop where it sat for FIVE MONTHS wasn't sure if it was broken because it wouldn't fire with no film in it.

I don't really have any sympathy for them...five seconds of googling could have told them it was fine.

Anyway, with the back out, it fires at 1/1000s only. With the back in, it won't fire at all. With the back AND film in it, it works as you would expect.

If you have it laying around, the backing paper of a 120 roll will fool the camera enough to let you test all speeds and functions.

**germar** · 05-31-2012, 11:27 AM

Thanks, all. I wound up buying the 645, along with a 75mm LS 2.8 and a 120mm f4 macro for a nice price. The seller had stuck an ancient roll of Porta 160 in there so all the functions could be checked. I'm running a fresh roll of Ektar through it now and we'll see how the images come out. I have high hopes.

excanonfd · 05-31-2012, 07:46 PM

Check the mirror damping foam inside the camera, if it's mushy or sticky, it's time to replace the foam. Finicky bit of work but straight forward enough for most diy'ers.

unixrevolution · 06-01-2012, 06:40 AM

Originally posted by germar

Thanks, all. I wound up buying the 645, along with a 75mm LS 2.8 and a 120mm f4 macro for a nice price. The seller had stuck an ancient roll of Porta 160 in there so all the functions could be checked. I'm running a fresh roll of Ektar through it now and we'll see how the images come out. I have high hopes.

Being as it is a Pentax and has really good Pentax glass on it, your hopes are justified!

The only thing these cameras are supposedly not good at is metering and setting the exposure accurately for slide film. Ken Rockwell says the camera only meters by full stops, but he's wrong. He also says you can compensate for third-stops by adjusting the camera's ISO setting...but that is also wrong. He thinks that by changing the ISO you slightly tweak the exposure, but you don't...you'd get the same nearest full-stop, since tweaking the ISO in third-stop increments would only change how it meters, not how it sets its exposure.

IF you shoot aperture priority, the camera can only change the shutter speed by full stops. Actually, I thought I read in the manual that it indicates the nearest full stop but it's actually stepless, though I don't have proof of that.

At any rate, even if the shutter DOES meter by only full stops, in Program or Tv, the camera can adjust its aperture by half stops, and there are half-clicks on the aperture ring, too.

Did any of that make sense?

**germar** · 06-01-2012, 07:58 AM

Actually, your post did help, thank you. I'll be getting the negatives back today and I'll try scanning them on my Canon flat bed tonight. I'm fully expecting user error issues in regards to exposure, especially with the 75mm LS lens ... which has no "A" setting and requires the shutter cocked open. We'll see what I end up with.

Not to hijack my own thread, but can anyone tell me if the 75mm LS lens is optically the same as the standard 75 "A" lens? Mine's in incredibly nice condition, but I sorta wish I had auto on the lens rather than the leaf shutter.

Thanks

Originally posted by unixrevolution

Being as it is a Pentax and has really good Pentax glass on it, your hopes are justified!

The only thing these cameras are supposedly not good at is metering and setting the exposure accurately for slide film. Ken Rockwell says the camera only meters by full stops, but he's wrong. He also says you can compensate for third-stops by adjusting the camera's ISO setting...but that is also wrong. He thinks that by changing the ISO you slightly tweak the exposure, but you don't...you'd get the same nearest full-stop, since tweaking the ISO in third-stop increments would only change how it meters, not how it sets its exposure.

IF you shoot aperture priority, the camera can only change the shutter speed by full stops. Actually, I thought I read in the manual that it indicates the nearest full stop but it's actually stepless, though I don't have proof of that.

At any rate, even if the shutter DOES meter by only full stops, in Program or Tv, the camera can adjust its aperture by half stops, and there are half-clicks on the aperture ring, too.

Did any of that make sense?

unixrevolution · 06-01-2012, 10:31 AM

I'm not sure if the optical formulas are the same, but I'll totally trade you my 75mm A for your 75mm LS lens.

PM me if interested.

05-29-2012, 05:04 AM	#1
germar Site Supporter Join Date: Apr 2007 Location: North Palm Beach, Florida Photos: Gallery Posts: 728	Buying a used 645 - What to look for? Hi, I'm about to take the jump into a Pentax 645 body and two lenses, all from an owner that sounds like she took good care of the gear. I've purchased a good bit of used equipment including some film bodies, but I thought I would ask those who know here if there are specific things I should be looking for when inspecting the 645. I know the ultimate test would be to run a roll of film through it, but I won't have the luxury. Any tips or troublespots I should look into? I'm hoping to find a nice "daily driver" that will allow me to play in medium format. Thanks in advance for any advice. germar

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05-29-2012, 05:38 AM	#2
aurele Veteran Member Join Date: Jan 2011 Location: Paris, France Photos: Albums Posts: 3,217	i never used 645 body, but i guess, do like every time you buy a used SLR : check that the mirror work, the lever, shoot on all speed (without film). Check exterior marks or scratch and check if it could have damaged internal mechanism. Open the back to be sur the curtain isn't damage. I may miss something but that's the big part.

05-29-2012, 06:08 AM - 1 Like	#3
Nesster Veteran Member Join Date: Oct 2006 Location: NJ USA Photos: Gallery Posts: 13,072	The 645 suffers from "over-helpful" automation; i.e. there's very little you can do with the shutter without the back + film in it. I've put together some bits and pieces about the camera here: Pentax 645 guide - Modern Photo Test 1985 - lens resolution the main posting is a repeat of the review I wrote here at pentaxforums: Pentax 645 - 645 Medium Format - Pentax Camera Reviews and Specifications

05-29-2012, 11:50 AM	#4
germar Site Supporter Join Date: Apr 2007 Location: North Palm Beach, Florida Photos: Gallery Posts: 728 Original Poster	Thanks guys. I've read your excellent resources, Nesster. I'm lead to believe this camera has been taken care of and hardly been used the past handful of years. I'll check the battery compartment for corrosion and make sure there's no overt signs of neglect. Can you "dry fire" the 645's shutter when the back is off? I know it will be 1/1000 but that would be better than nothing. Again, thank you. germar

05-31-2012, 10:04 AM	#5
Smolk Pentaxian Join Date: Feb 2010 Location: Eerbeek Photos: Gallery \| Albums Posts: 1,857	On the 645, the diopter ring can actually be a bit loose which means you need to adjust it when you use the camera. Not a deal breaker but nice when it's in proper order.

05-31-2012, 10:41 AM	#6
unixrevolution Veteran Member Join Date: Apr 2009 Location: Waldorf, MD Photos: Gallery \| Albums Posts: 1,861	Originally posted by germar Thanks guys. I've read your excellent resources, Nesster. I'm lead to believe this camera has been taken care of and hardly been used the past handful of years. I'll check the battery compartment for corrosion and make sure there's no overt signs of neglect. Can you "dry fire" the 645's shutter when the back is off? I know it will be 1/1000 but that would be better than nothing. Again, thank you. germar I actually got a 645 on the cheap cause the pawn shop where it sat for FIVE MONTHS wasn't sure if it was broken because it wouldn't fire with no film in it. I don't really have any sympathy for them...five seconds of googling could have told them it was fine. Anyway, with the back out, it fires at 1/1000s only. With the back in, it won't fire at all. With the back AND film in it, it works as you would expect. If you have it laying around, the backing paper of a 120 roll will fool the camera enough to let you test all speeds and functions.

05-31-2012, 11:27 AM	#7
germar Site Supporter Join Date: Apr 2007 Location: North Palm Beach, Florida Photos: Gallery Posts: 728 Original Poster	Thanks, all. I wound up buying the 645, along with a 75mm LS 2.8 and a 120mm f4 macro for a nice price. The seller had stuck an ancient roll of Porta 160 in there so all the functions could be checked. I'm running a fresh roll of Ektar through it now and we'll see how the images come out. I have high hopes.

05-31-2012, 07:46 PM	#8
excanonfd Veteran Member Join Date: Jan 2010 Location: Vancouver, BC Posts: 1,421	Check the mirror damping foam inside the camera, if it's mushy or sticky, it's time to replace the foam. Finicky bit of work but straight forward enough for most diy'ers.

06-01-2012, 06:40 AM	#9
unixrevolution Veteran Member Join Date: Apr 2009 Location: Waldorf, MD Photos: Gallery \| Albums Posts: 1,861	Originally posted by germar Thanks, all. I wound up buying the 645, along with a 75mm LS 2.8 and a 120mm f4 macro for a nice price. The seller had stuck an ancient roll of Porta 160 in there so all the functions could be checked. I'm running a fresh roll of Ektar through it now and we'll see how the images come out. I have high hopes. Being as it is a Pentax and has really good Pentax glass on it, your hopes are justified! The only thing these cameras are supposedly not good at is metering and setting the exposure accurately for slide film. Ken Rockwell says the camera only meters by full stops, but he's wrong. He also says you can compensate for third-stops by adjusting the camera's ISO setting...but that is also wrong. He thinks that by changing the ISO you slightly tweak the exposure, but you don't...you'd get the same nearest full-stop, since tweaking the ISO in third-stop increments would only change how it meters, not how it sets its exposure. IF you shoot aperture priority, the camera can only change the shutter speed by full stops. Actually, I thought I read in the manual that it indicates the nearest full stop but it's actually stepless, though I don't have proof of that. At any rate, even if the shutter DOES meter by only full stops, in Program or Tv, the camera can adjust its aperture by half stops, and there are half-clicks on the aperture ring, too. Did any of that make sense?

06-01-2012, 07:58 AM	#10
germar Site Supporter Join Date: Apr 2007 Location: North Palm Beach, Florida Photos: Gallery Posts: 728 Original Poster	Actually, your post did help, thank you. I'll be getting the negatives back today and I'll try scanning them on my Canon flat bed tonight. I'm fully expecting user error issues in regards to exposure, especially with the 75mm LS lens ... which has no "A" setting and requires the shutter cocked open. We'll see what I end up with. Not to hijack my own thread, but can anyone tell me if the 75mm LS lens is optically the same as the standard 75 "A" lens? Mine's in incredibly nice condition, but I sorta wish I had auto on the lens rather than the leaf shutter. Thanks Originally posted by unixrevolution Being as it is a Pentax and has really good Pentax glass on it, your hopes are justified! The only thing these cameras are supposedly not good at is metering and setting the exposure accurately for slide film. Ken Rockwell says the camera only meters by full stops, but he's wrong. He also says you can compensate for third-stops by adjusting the camera's ISO setting...but that is also wrong. He thinks that by changing the ISO you slightly tweak the exposure, but you don't...you'd get the same nearest full-stop, since tweaking the ISO in third-stop increments would only change how it meters, not how it sets its exposure. IF you shoot aperture priority, the camera can only change the shutter speed by full stops. Actually, I thought I read in the manual that it indicates the nearest full stop but it's actually stepless, though I don't have proof of that. At any rate, even if the shutter DOES meter by only full stops, in Program or Tv, the camera can adjust its aperture by half stops, and there are half-clicks on the aperture ring, too. Did any of that make sense?

06-01-2012, 10:31 AM	#11
unixrevolution Veteran Member Join Date: Apr 2009 Location: Waldorf, MD Photos: Gallery \| Albums Posts: 1,861	I'm not sure if the optical formulas are the same, but I'll totally trade you my 75mm A for your 75mm LS lens. PM me if interested.