Camera leaking light, bad development or just underexposed images?

Thomas Hyttel · Aug 6, 2018

I shot a roll of 120mm on my new Pentax6x7 and used an iphone app for metering. I can see that I underexposed some images, but all the pics are also washed out... so I suspect that the camera is leaking light? But could it also be a bad development? I got the roll developed and scanned at a lab.

I also have one more beginner-question: the scans I got wasnt all inside frames - some has a black bar between them. Why is this?

MattKing · Aug 6, 2018

Welcome to Photrio!
It is always difficult to analyze film results based on scans. Problems may or may not originate from the scanning step.
If possible, please backlight your negatives and then take a digital photo of the results - including the edges of the film.
If we can see that, we may be able to help more.
FWIW, these results look typical for when a scanner is attempting to struggle with seriously under-exposed negatives.
One final tiny point - it is 120 film, not 120mm film. If the 120 designation referred in some way to the size, 120mm film would be bigger than four inches across.

glbeas · Aug 6, 2018

Its not a light leak. From what I see its most likely underexposure, though there is one frame that shows a lightstrike on the edge like you see on the leader of 35mm film, camera back may have been opened at some point when it shouldnt have. The black bar is simply the space between frames, the automated frame centering on the scanner doesnt work too well with thin negatives.

Poisson Du Jour · Aug 6, 2018

The first image is over-exposed while subsequent images show gross underexposure.
Use a proper hand-held light meter for metering (not an iPhone!), or if the Pentax 6x7 has a TTL meter, use that.

As Matt said above, scans may not tell the full story and cannot be taken as evidence of a problem one way or another. The best diagnosis can only be made if the negatives/transparencies are viewed on a lightbox.

Having said the above, two of the images show evidence of light piping, caused by the roll not being tightly wound and taped after exposure, with light striking the edges, leading the the characteristic flaring. 120-format rolls are prone to light leaks and should be shielded from all stray light, and definitely load and unload rolls in subdued light -- throw a jumper or something over yourself and the camera when going through the film loading/unloading process and wrap the exposed roll in tin foil.

The last image may be incomplete shutter travel or frame overlap, which is common in the older Pentax 6x7 cameras (a problem that was corrected in the later 1989-era Pentax 67 bodies) and can indicate a service of the shutter is required.

There may be other problems with the camera, your technique (metering, exposure and scanning) or the processing.

Thomas Hyttel · Aug 6, 2018

Thanks for the reply!
I will try to fint a way to backlight the pics and upload them - but it seems like they are very underexposed since theres almost no info on many of them, so I think youre right! The lightmeter-app on my phone is apparently very bad

Thomas Hyttel · Aug 6, 2018

Poisson Du Jour said:
The first image is over-exposed while subsequent images show gross underexposure.
Use a proper hand-held light meter for metering (not an iPhone!), or if the Pentax 6x7 has a TTL meter, use that.

As Matt said above, scans may not tell the full story and cannot be taken as evidence of a problem one way or another. The best diagnosis can only be made if the negatives/transparencies are viewed on a lightbox.

Having said the above, two of the images show evidence of light piping, caused by the roll not being tightly wound and taped after exposure, with light striking the edges, leading the the characteristic flaring. 120-format rolls are prone to light leaks and should be shielded from all stray light, and definitely load and unload rolls in subdued light -- throw a jumper or something over yourself and the camera when going through the film loading/unloading process and wrap the exposed roll in tin foil.

The last image may be incomplete shutter travel or frame overlap, which is common in the older Pentax 6x7 cameras (a problem that was corrected in the later 1989-era Pentax 67 bodies) and can indicate a service of the shutter is required.

There may be other problems with the camera, your technique (metering, exposure and scanning) or the processing.

Thanks a lot! I will try to shoot a new roll with that in mind. I think the processing is correct since it was done at a lab - I was just suspecting it since the black bar / space between frames also have the same dark grey / washed out color as the rest of the pictures.

Old-N-Feeble · Aug 7, 2018

I agree with the others. They all appear grossly underexposed. I also agree with the edge fogging due to light leaking through loose paper. Additionally, I suspect a little mishandling at the lab. I might be mistaken but it appears the film was slightly bent in one or two places at the lab (green arc shape in #2 and green bright marks in #4 an #6). Image #6 appears to have been scratched.

pentaxuser · Aug 7, 2018

Poisson Du Jour said:
The first image is over-exposed while subsequent images show gross underexposure..

What is it about the first frame that indicates it is over-exposed compared to the fourth or fifth frame which seems to have the same slightly milky/misty look. I ask this question because I'm looking to be educated in over/under exposure. This is not a challenge.

pentaxuser

Poisson Du Jour · Aug 7, 2018

pentaxuser said:
What is it about the first frame that indicates it is over-exposed compared to the fourth or fifth frame which seems to have the same slightly milky/misty look. I ask this question because I'm looking to be educated in over/under exposure. This is not a challenge.

pentaxuser

I understand your interest.
The images shown are not at all representative of a normal or even ballpark exposure with the Pentax 67, and even with a separate light meter (he used an iPhone app), the exposure would be better than anything shown in the samples. The fourth pic you mention appears to have grossly insufficient light, and it's either poor exposure or a problem with the camera's shutter (or both). There is incomplete travel of the shutter shown in the sixth image.

It is hoped the OP will run another test and post the results here. Until then, a lot of speculation as to what the cause could be, but still some pointers.

Also, the possibility of grossly expired and/or damaged film comes to mind. I would want to see another roll of exposures before settling on any one or multiple diagnosis.

Sirius Glass · Aug 7, 2018

Underexposed.

pentaxuser · Aug 8, 2018

Thanks,Poisson du Jour. Yes some are grossly under-exposed such that there can be no debate, I'd have thought. The two frames that look almost identical are 1 and 5 i.e. the rowing boats on the lake and the man sunbathing on a rock on a grassy slope. I have real difficulty distinguishing between them, hence my question as to why the first was overexposed and the fifth was under-exposed.

I have since remembered another thread. The OP's frames resemble but are worse than those of someone based in England(Eckybedmond, I think he called himself) who had taken pictures of the seaside that had similar but slightly less milkiness. He had however taken one that was either correctly exposed or possibly slightly over-exposed and it looked quite different to the first frame in this OP's frames.

I'd now conclude that all frames are under-exposed as Sirius appears to be saying

pentaxuser

abruzzi · Aug 8, 2018

If your roll is significantly underexposed, I suspect the “black bar” is just the space between frames. I’ve occasionally encountered automated scanning services not properly centering the frames, probably because it has a hard time automatically detecting the frame beginning.

benjiboy · Aug 8, 2018

I have a light meter app in my smartphone too Thomas, but I don't use it because it underexposes by about two stops as well, so it's about as much use as a one-legged man in an ass-kicking contest. I suggest you buy yourself a modern digital light meter made by Sekonic or Gossen.

glbeas · Aug 8, 2018

Just out of curiousity I looked at a light meter app, of course the reviews all said it was accurate but forgetful. Do these apps have a way to be calibrated to the sensor in the phone?

Chan Tran · Aug 8, 2018

All of them are underexposed. Underexposed looks washed out when trying to scan lighter or print lighter.

Ces1um · Aug 8, 2018

abruzzi said:
If your roll is significantly underexposed, I suspect the “black bar” is just the space between frames. I’ve occasionally encountered automated scanning services not properly centering the frames, probably because it has a hard time automatically detecting the frame beginning.

I agree. This looks like Epson's software in thumbnail mode just not finding a distinct edge to the frame.

removed account4 · Aug 8, 2018

hi thomas

you mention this is a new ( to you ) pentax ... have you had the shutter CLA's since you bought it ?
is it new film or old film ? have you ever used that metering app for other photography and how did the images look?
looks like the film didn't get enough light could have been user error? or mechanical failure ? or old film purchase ...
sometimes old film needs more light or the development needs to compensate for underexposure .. or the app is wonky..

have fun with your new camera !
john

Sirius Glass · Aug 8, 2018

Underexposure comes from four sources:

Wrong ISO setting
Inaccurate meters
Cameras out of adjustment and needing a CLA
Metering with the sun or sky in the sensor view

Thomas Hyttel · Aug 8, 2018

jnanian said:
hi thomas

you mention this is a new ( to you ) pentax ... have you had the shutter CLA's since you bought it ?
is it new film or old film ? have you ever used that metering app for other photography and how did the images look?
looks like the film didn't get enough light could have been user error? or mechanical failure ? or old film purchase ...
sometimes old film needs more light or the development needs to compensate for underexposure .. or the app is wonky..

have fun with your new camera !
john

The film is a new roll of portra 400 - I will try to shoot a roll today with correct exposure, and also find a way to upload the negatives soon

abruzzi · Aug 8, 2018

I was once told that the P67 shutter is quartz timed and therefore very accurate, and short of significant mechanical issues will remain accurate compared to a mechanically timed shutter. I don’t know how much truth there is to that, but...I’d lean towards a metering issue. I’d say go out on a sunny day, ignore the meter, and shoot sunny 16.

Thomas Hyttel · Aug 8, 2018

abruzzi said:
I was once told that the P67 shutter is quartz timed and therefore very accurate, and short of significant mechanical issues will remain accurate compared to a mechanically timed shutter. I don’t know how much truth there is to that, but...I’d lean towards a metering issue. I’d say go out on a sunny day, ignore the meter, and shoot sunny 16.

I remember shooting mostly (e.g. the 1st and the 5th image) at F11 and 1/1000 (guided by a lightmeter app) with iso 400 film. Is that similar to around f/16 and 1/500s? It was a very sunny day.

MattKing · Aug 8, 2018

Thomas Hyttel said:
I remember shooting mostly (e.g. the 1st and the 5th image) at F11 and 1/1000 (guided by a lightmeter app) with iso 400 film. Is that similar to around f/16 and 1/500s? It was a very sunny day.

That should give you decent exposure.
Is there any chance you had a polarizer or ND filter on the camera?

Thomas Hyttel · Aug 8, 2018

MattKing said:
That should give you decent exposure.
Is there any chance you had a polarizer or ND filter on the camera?

Yes thats what im confused about - that they look so far from correct exposure. No I didnt have ND or polarizer on. Also I didnt have a lens shade on, but I shot with the sun in my back.

abruzzi · Aug 9, 2018

Thomas Hyttel said:
I remember shooting mostly (e.g. the 1st and the 5th image) at F11 and 1/1000 (guided by a lightmeter app) with iso 400 film. Is that similar to around f/16 and 1/500s? It was a very sunny day.

Yeah, f11 and 1/1000 on a 400 speed film should have come out fine on that first shot. If, as you say, the film was a fresh (not old expired) roll of portra 400, I’m out of ideas.

Agulliver · Aug 9, 2018

I've not tried an iPhone, but I have used two Android light meter apps and while it can be difficult to match the phone's image to that in the viewfinder of your camera....the phone apps have always been "in the ballpark", as they say. Using an app has never resulted in grossly over or under exposed images for me. The app also tends to back up my own instincts.

You mention f11 and 1/1000 on a sunny day. The old "sunny 16" rule would indicate 1/400 at f16 or 1/800 at f11 so again you're in the right ballpark...and even if you under-exposed by a stop or two the images would be usable. It looks like the scanner is really struggling with very thin negatives. Colour negative film reacts better to over-exposure however, so perhaps over expose by a stop compared to your app's recommendation?

It will be interesting to see the actual negatives, and how your second roll comes out.

Camera leaking light, bad development or just underexposed images?