2016 November 27

Lens Slate is a free photography app for iOS and Android to help you keep track of the configuration of manual lenses as you shoot.



How do I install Lens Slate?

Open the app web page in

and follow the instructions.


How do I update Lens Slate?

Lens Slate will be automatically updated to the latest version when you open it and the network is available.


How do I use Lens Slate?

Follow the instruction in the manual.


How do I delete Lens Slate?

You can delete Lens Slate from your device exactly as you would any other app.


How can I get support for Lens Slate?

You can send email to lensslate@gmail.com.


Why is it called Lens Slate?

It’s a reference to the chalkboard slates used in movie-making to show information about the scene being shot.


Is Lens Slate free?

Yes, Lens Slate is free software licensed under the GPL.


Why doesn’t Lens Slate install from the App Store?

The App Store is for native apps; Lens Slate is a web app rather than a native app. You install web apps by simply saving a web page to your home screen. However, despite being a web app, Lens Slate runs locally and does not require a network connection.


Why doesn’t Lens Slate work with Firefox on Android?

I don’t know. I’m working on this, but I’m not very familiar with Android and in particular don’t have an Android device for testing, so progress is slow.


How did you come up with the idea for Lens Slate?

I tried a couple of different ways to record the configuration of my manual lenses (recording a short video clip and taking a photo of my fingers showing the aperture in stops), but they seemed very awkward.

I came up with the idea of writing the configuration on index cards and taking a photo. That quickly evolved into setting the configuration on a local web page on my iPhone and taking a photo. Then I realized I didn’t need to take the photo with my camera; I could just take a screenshot.


Why can’t Lens Slate write the lens configuration into the EXIF metadata of my images?

Here’s how I think Lens Slate should work:

That would be great; no more messing about with screenshots. This is how geo-tagging apps typically work.

The first part — writing the data base on your device — is easy. The rest of it — transferring the data base to your computer and then writing the EXIF metadata to your images — is much more work. At the moment, I don’t have time take it on.


Can I use Lens Slate with film cameras?

Yes, but since film images don’t typically have time stamps, you’ll have to figure out a means to associate the lens configuration screenshots and the images. This might be as simple as making sure you take one (and only one) screenshot for each image or writing the exposure number in the notes area.

You might also like to write the camera body and the film type in the notes area.


Why doesn’t Lens Slate have a button to take a screenshot?

To take a screenshot and save it in the camera role on your device:

I agree that these can be awkward and it could be more convenient if Lens Slate had a button to take a screenshot.

It is possible for a web app to generate a screenshot, but a web app can’t save it to the camera roll. So, any solution along these lines would require either converting Lens Slate to a native app (to have access to the camera roll) or require server-side help (to save the images on a server). I don’t have the time or resources to pursue these possibilities.


© 2016, 2018 Alan Watson Forster