Pinhole photographers! How do you guess the exposure?

[Donald Qualls]

Given that there are more Android users out there I wonder why the developers of these Apps do not go for the larger user base.

I'm guessing they're Apple cultists.

 

[MattKing]

If I understand things correctly, there is considerably more variation between devices that use the Android platform than there is between devices that use iOS.
You need to have a significant amount of customer support resources to support a platform with wide variation in how it is implemented.

 

[DWThomas]

In a moment of fantasy I can imagine there is some sort of "package" that brings whatever system calls are available in Android or iOS up to a common abstraction layer which ones actual app code would connect to. Thus the bulk of the app could be common to all and compiled/linked to some intermediate library. But this would be rubbing elbows with the big boys doing commercial apps for banks and retail chains which might mean the cost of the package would be way beyond the means of hobbyists and tinkerers. So far I've managed to resist any urge to learn more about what is necessary to do smartphone apps; I have enough flat spots on my head from other software efforts back when I was working.

 

[rst]

If I understand things correctly, there is considerably more variation between devices that use the Android platform than there is between devices that use iOS.
You need to have a significant amount of customer support resources to support a platform with wide variation in how it is implemented.

Yes true, but then, what is needed is not that sophisticated as that it would not be provided by the OS as some kind of standard library, I mean reading from the camera, reading input from some keyboard and handling a timer. And for all that you do not even have to learn a proprietary programming language. But maybe the intended audience itself is so small ...

 

[Donald Qualls]

I already have a (free) light meter app that works equally well on my first-gen Pixel phone, and on my Amazon Fire HD 10 (2017) tablet -- despite the tablet using a version 5 Android modified and maintained by Amazon, and the Pixel having Android 10. Building apps to lowest serviceable version is common procedure in the Android world, and yes, building to packaged libraries is also common (as note that there is very little commonality in display or camera hardware between these two devices). The rest of the functions of Pinhole Master are very generic database and computation, albeit quite nicely integrated -- most of it could have been done in real time on my first DOS machine, in 1987.

Given that metering through the camera is likely to be the only hardware-specific function (for display, there are standard system calls that return display resolution, aspect ratio, orientation, etc., and the camera software created by each phone manufacturer has a reasonably standardized API for exactly this need), the argument that Android has a much wider range of hardware, while valid, isn't really an obstacle, any more than the bewildering array of non-Apple computer hardware prevents writing applications that will run on nearly any hardware that runs a broad range of Windows or Linux versions (Linux is the basis for Android).

 

[Grandpa Ron]

Like many I use a light meter. I like to shoot at f 360, so I take a meter reading at f 22 and do the math.

Since f 360 is eight full f stops way from f 22 and exposure time doubles with each stop; doubling eight time give me a time multiplier of 256.

Also like many others I made a spread sheet for each light meter reading. If the exposure get really long (say over 2 minutes) I generally add some for reciprocity.

 

[Roger Thoms]

I use a Gossen Luna Pro SBC to meter my exposure, then read the time at f128 and apply a correction factor that I calculated use Joe Van Cleaves method that he spells out in this video. Finally I use this app to adjust the time for reciprocity failure. https://apps.apple.com/us/app/reciprocity-timer/id459691262. So not exactly guessing, but that’s my current method.

Roger

 

[tbransco]

+! for Joe van Cleave's method.

 

[cliveh]

For pinhole photography, you don't need a light meter, as repeated experience will soon give you an idea about the best exposure time.

 

[Donald Qualls]

For pinhole photography, you don't need a light meter, as repeated experience will soon give you an idea about the best exposure time.

Unless, of course, you're trying to capture an image in different light than your usual, and perhaps won't get to bracket (I had exposures with my CCB camera on Foma 100 that ran to four hours plus recently, including reciprocity correction -- not going to make two more of those, at two hours and eight hours, just to be sure).

If you need to get it right the first time, meter, correct for your aperture, apply reciprocity correction for your film -- and you'll usually get close enough to get a good negative. And then sometimes you won't, because pinhole isn't a fully exact science.

 

[Roger Thoms]

For pinhole photography, you don't need a light meter, as repeated experience will soon give you an idea about the best exposure time.

I think it depends. Like with my 8x10 pinhole camera shooting film @ about 6 usd a sheet I definitely use a meter. If I'm playing around with paper negatives and am near a darkroom then no meter. I'll make an exposure, develop it and then make exposure adjustments on the next shot.

Roger

 

[djkloss]

When I got my Ondu 8x10 I knew it would be really expensive to shoot at $6.00 a sheet, so there's no room for guessing - on composition or exposure. I've only been doing pinhole for a little over a year. I envy the people that can guess and get it right. I wasn't ready to trust the Ondu cheater chart nicely engraved on wood without testing it and comparing it with 3 other meters, a reciprocity correction chart and a few spreadsheets. After I did all the testing I discovered much to my delight that it really was ok to use and it was a lot quicker than analyzing. The thing that makes it work though, is a good meter - the gossen luna pro is my go-to meter for over 20 years. It goes up to f/128 and down to f/.1 or something. An amazing instrument! Anyway... like any thing worth the effort, If I wanted to learn to guess, I might go out for a day with no camera, and just a light meter. Challenge myself starting with sunny 16 rule and check it with the meter. practice practice practice as my piano teacher used to say Even with my oatmeal pinhole cameras, I still use a meter. Hope this helps, and most of all have fun!

 

[Donald Qualls]

That 8x10 is probably mainly intended for paper negatives. I've shot a fair amount of pinhole, built and converted cameras, and there is no way I'd put a $6 sheet of film into a pinhole camera without at least having a high level of experience-based confidence in the images it produces -- perspective, exposure (including wide angle fall-off), light leaks or lack thereof, etc.

Paper negatives not only cost a lot less than 8x10 film, they make it easier to make accurate exposures with a lens-cap type shutter in bright sun conditions -- EI 6 (or even EI 25) vs. ISO 100 can make the difference between an exposure you can't reliably make with a manual open, manual close shutter and one you can.

 

[Grandpa Ron]

I have to agree with Qualls. At six bucks a sheet I would be looking for an alternate.

Since I am an incessant tinkerer, I would be looking for a way to mount 4x5 film in my 8x10 camera. You of course will lose much of the image but you will get four time the number of shots to develop the exposure information you want.

Good Luck

 

[djkloss]

4x5 after 8x10 just seems so tiny and especially when putting it behind a frame. I chose the 8x10 format so I could do alternative processes and not have them disappear because of their size. Seems like no one notices the little ones at shows/exhibits. maybe it's just me.

 

[Grandpa Ron]

I agree that 4x5 is tiny when compared to 8x10, 1/4 to be exact. but unless you are are rich or lucky, you are going to burn a lot of film perfecting your skills.

Interpreting light meter readings, notes, and an exposure charts; plus film developing methods are usually learned by trial and error.