Answers to some frequently asked questions.

Why are there several films with the same name ? for instance there are 4 choices for HP5 : HP5 (WO lenses),HP5+, HP5+ (Bond), HP5+(Gainer). What are the Gainer, Bond, WO ?

Short answer : Gainer, Bond are the name of person who computed alternate reciprocity curves. In doubt, ‘official ‘ film ;for Ilford HP5+, the one with subtitle ‘Ilford official data’.

Long answer : There are currently several reciprocity curves, with slight differences. Under each film name, there is a subtile : for instance « Ilford official Data » or « Gadget Grainer, APUG forum, sept 2005 ». These subtitles elucidate the source of the data. Pressing the (i) button you can view the data and find the URL where you can cross check it.
The difference are minimal, but are important for some expert users, especially in astrophotography.

Is there is a limit to the focal length choice (distance from pinhole to filmplane). My camera is 255mm and is outside of the calculation range available.

You can select a range tab for thefocal plane. The large range goes up to 10 meters. 

I am wondering why the EV reading is so large on the metering screen and how I can turn it off?

There is no way to remove the big EV display.

once a film is selected does it automatically compensate for reciprocity in the meter reading?

And yes, the exposure displayed takes into account the film reciprocity. You can display both time without reciprocity and time with reciprocity by tapping briefly on the time display. The value named « Metered Exposure » is the pre-reciprocity exposure, the value named « Exposure » is after compensation?

The exposure displayed takes into account the film reciprocity. You can display both time without reciprocity and time with reciprocity by tapping briefly on the time display.

I am using a Leica M6 with a Daystar lasers 0.24mm pinhole lens cap attachment. What is the diaphragm diameter setting on the aperture calculator? Is this the diameter of the leica M mount (so 44mm)? If so, the calculator suggests an aperture of f0.6 but that doesn’t seem right. Or is the diaphragm diameter simply the pinhole diameter (0.24mm) in which case the aperture is f116.

The vocabulary is not consistent in the app, I need to fix that.
The pinhole diameter and the diaphram diameter are two names for the same thing : the size of the hole : 0.24 mm in your case (very close from tthe optimal size of 0.22mm), the second number necessary is the distance from the film to the cap.
I found a discussion on the web here : https://www.photo.net/discuss/threads/m6-as-a-pinhole-camera.24708/

*The focal length of a pinhole 'lens' is equal to the distance from the film: Since (thanks to Erwin and the Hexar debate) we know the film/ flange distance of the Leica-M is 27.xx millimeters. then a 'bodycap' pinhole mount will be a 27mm (+/-) optic. I guess on a Hexar it would be a 28mm (+/-) - and clearly inferior. 8^)*

so you can use 27 as the focal length

II use a pinholecap for my digital camera. What is the focal length ?

In that case, it is the Flange focal distance.
if you are in digital pinhole, it might be quite difficult to know the distance between the sensor (or film) of your camera, and the pinhole (usually set in a cap). This wikipedia page list this distance for virtually all type of camera. Use the value provided as the focal length in the Pinhole Assist settings. https://en.wikipedia.org/wiki/Flange_focal_distance

when doing an export of the log would it be possible to also export the thumbnails?

You can export individually a log as an image with all information as a photo.

When I measure with my iPhone XS Max and in comparison with my Sekonic L-208 light meter. Measurement results differ with two apertures. So, sekonic sees everything two fades brighter, i.e. iPhone cameras. I trust my Sekonic light meter more. How can you comment on that ?

let me explain how pinhole assist measure light. The app connect to the iphone camera and *observe* how it work : aperture, exposure time, ASA. It then computes the light value. all *real* measure are done by the iphone hardware/software.

The iPhone camera has a different geometry compared to a cell. The value is naturally different.

You can the ability to adjust pinhole assist ! Go the the settings, scroll dow until you find « cell offset ». Choose your offset between -2 and +2.

I’m trying to use Pinhole Assist with my pinhole camera. I will be using Arista EDU Ultra 100 4x5 film but I want to expose it at ASA 64. When I change the ASA, Pinhole Assist changes the film type and reciprocity away from Arista EDU. How can I adjust the ASA setting without effecting the film type and reciprocity setting?

The film speed and the reciprocity curve are linked. This is a good feature when you start shooting, but for expert users it can be annoying.

You can achieve 64 ASA 2 ways:
  • underexpose the 100 ASA Arista by ½ IL using EV correction (just below the camera view) =: 1/2 ASA will get you to 70 ASA (not far)
  • or create a new reciprocity curve: go the the reciprocity film film, tap the circled « i » button at right side, then scroll to the bottom of the film description and tap « duplicate ». Go back to the list of films : the is a new film named Arista EDU 100 followed by a criptic set of chars : D454FG44. This is the copy. You can edit it and change the ASA value to 64, rename the film as you want : "Arista EDU 100 (64) » and you're done.

I do not see a polarizer filter in the filter section. Am I mistaken or can this be added?

Polarizing filters reduce the light passed through to the film or sensor by about one to three stops (2–8×) depending on how much of the light is polarized at the filter angle selected.
It means that when you rotate the filter you change the stop. Therefore pinhole assist cannot know the number of stops to apply.
You can define you own filters in pinhole assist and tweak the value by rule of thumb. I am afraid it is not possible to do more. 

My camera name is not in thel ist, and the and the aperture is 183. Inly 180 is avialable in thrl ist of paerture. Hox do I do ?

You can set the aperture to the nearest number available (f180) via the button with the diaphgram icon. The difference between f183 and 180 is almost non existent.

you can also in the main menu add a combo aperture+film : set the aperture to 180 or enter pinhole size and focal distance, aperture will be calculated.

Je voudrais acheter l'appli "Pinhole Assit" dans une ancienne version, compatible avec IOS7.1.2 Comment faire ? Je ne trouve que la dernière version sur l'apple store.

When you buy rhe app, you will get an older version, compatible with your phone. It will not have all the feature from the current version.

Any plan for an Android version ?

No. Not in the near future. Neither in the long term. I did develop Pinhole Assist as a hobby. I am still trying to do photography. Building an Android version would be too time consuming. And the Android market is so fragmented: so many phones. So many screen sizes. So many Android versions.

Do you have support for the Luxi diffusion dome ? (Lumu)

The good news : yes you can. Theoretically. I have not tested it, because I do not have a Luxi. Here are the steps
  1. Go to the settings, and enable "incident light front cell'.
  2. Set « K incident front cell) » to 330

Now put your luxi on the front camera and it should work. Please tell me about your results.

Any plans to integrate the Lumu light meter for iphone ? (Luxi)

For the time being, Lumu has not made a SDK available (1/3/2014). As soon as their SDK is available, I will try it.

(2014) Does it support IoS 6 and IoS 5 ?

Yes:the App Store will propose you to load a former version which looks ike this. Do not use iTunes on your mac or PC, use your device to download it.


As of 2014 : For the time being the two version (ios 5&6) and iOS7 have the same capabilities, but a different GUI. When the features will differ significantly, I will reduce the price of the old version.

(2016) Does it support IoS7 and iOS8 ?

Beginning with version 4.0 (may 2016), Pinhole Assist Requires iOS9. Owner of ioS7 devices (Iphone 4) will have access to PinholeAssist 3.7.1 If you have a device with ios8, i recommend you upgrade to ios9, or use version 3.7.1

Réponses à quelques questions fréquemment posées.

Quand ferez vous une version Android ?

Sans doute non. Mon hobby principal est a photographie, et développer une version Android me prendrait trop de temps.

Ferez vous une version qui gère la cellule Lumu ? (

A cette date (1/3/2014) le SDK de cette cellule n’est pas disponible.
En 2016, il l'est. Il va falloir que je fasse quelques chose….

Ferez vous une version qui gère le diffuseur Luxi ? (

En fait, elle est déjà là.Mais je ne l’ai pas testé. Pinhole Assist gère les dômes de diffusion
  1. Allez dans les réglages et autorisez « incident front cell »
  2. Réglez le facteur K « K (incident method ») et réglez le sur K=330

Mettez le luxi sur la caméra frontale. C’est bon.