Kodak brownie pinhole images issue

[sc0ttie]

I have finally got around to having my 120 film developed and printed and got my prints back today.
The images seem to have a very strong circle vignette around them, like this shot (which is not my shot I have just linked it from HERE for illustrative purposes)

So what do I need to do to my Brownie pinhole conversion in order to not have the strong black circle around my images? I like a soft vignette but the circle just looks pants to me. :|

 

[Alastair]

I doubt it's a vignette, it's just the image circle being thrown by the pinhole.

Why not put up some of your prints?

 

[sc0ttie]

I could do but they were not interesting subjects, I just pointed it to a field and do shots 5secs - 20 seconds in 5 second increments to see how the exposure is.

Is there a way to shoot pinhole without such a pronounced black circular border though? Is it anything to do with the pinhole being behind the lens inside the camera and distance to the film plane? Should I put the pinhole in front of the lens for my next film?

 

[Yv]

Now maybe I am applying a crazy female logic here, but isn't it because the 'pinhole' is a circle shape and the distance from hole to film plane is not long enough to give the 'spread' of the image to cover the square film area?

 

[sc0ttie]

Now maybe I am applying a crazy female logic here, but isn't it because the 'pinhole' is a circle shape and the distance from hole to film plane is not long enough to give the 'spread' of the image to cover the square film area?

Not sure about the female logic bit but the rest sounds good

I wonder if your amazing female logic can answer this bit too if I take the lens off and put the pinhole in its place (thus further from the film plane) does that increase the 'spread' of the image or does that introduce other problems?

 

[Yv]

no bloody idea...I guess though that the pin hols is much smaller than the lens 'aperture' ergo the problem. How you solve requires a far more technical mind than mine. IN theory, the further the pinhole is from the film, the bigger the spread will be but after that..... :shrug:

 

[raathistle]

Try this site, it will tell you wht image circle you can achieve for a given focal length and aperture of pinhole

http://www.mrpinhole.com/calcpinh.php

For a 120 camera, I think the minimum you can realistically get away with is something in the 50-60mm range, unless you curve the film plane

 

[donut]

no bloody idea...I guess though that the pin hols is much smaller than the lens 'aperture' ergo the problem. How you solve requires a far more technical mind than mine. IN theory, the further the pinhole is from the film, the bigger the spread will be but after that..... :shrug:

thats the trouble with you girlies ,you try and get all technical ,then you're in over your heads , leave it to the blokes ,now where were we ,oh yes ,,,,,
what she said ...................

 

[Jared]

Square hole?

 

[TheBigYin]

Is the plate with the pinhole at the front of the camera, or recessed into the body?

If the pinhole is not at the very front of the camera, anything in front of it will block the light, causing those black porthole ring type images. My Holga panoramic camera needed the shutter surround hole "relieving" a little to prevent the customary holga dark corners on the 6x12 film mask.