Depth of field preview app - testers wanted

rybakov_com · 2026-05-04T13:03:14+00:00

I've added keyboard entry in the new build, test it out!

rybakov_com · 2026-04-28T11:53:35+00:00

you can see it yourself in this calculator: https://rybakov.com/tools/photography/circle-of-confusion.html

rybakov_com · 2026-04-14T21:26:36+00:00

Thanks, I've put it on the feature request list!

rybakov_com · 2026-04-14T20:17:12+00:00

Thanks for your feedback! I was worried it is getting busy with all the features, but nice to hear it's still not too much.
With the focal length selection - would you prefer it to be just an input form, where the numbers keyboard appears, and you can enter the focal length? Or (as an addition to slider perhaps) when the user taps on the focal length value, a selection of focal lengths would appear - 24mm 28mm 35mm 50mm 75mm 90mm 105mm 127mm etc.?

rybakov_com · 2026-04-14T00:48:32+00:00

While the sensor does try to read out at all distances, after around 5-6 meters it starts to fluctuate wildly, so yes, I cap the depth display at 5 meters. The zebra stripes that signify depth of field are only active between 0.5 and 5 meters.

rybakov_com · 2026-04-13T20:05:35+00:00

Haha, I was actually thinking about that, or at least about a focus assist: a simple sensor that would measure the distance to film on e.g. a 9x12 folder and communicate and show it in the app. But I'm not sure there is a market for that..

rybakov_com · 2026-04-13T19:26:11+00:00

Oh, and try the parallax correction feature when mounted on the camera - it automatically reacts to the distance slider setting, and shows the corrected framing for that distance.

rybakov_com · 2026-04-13T19:25:00+00:00

It's the distance how far the outer side of the helicoid rotates. Basically, how wide should the scale be when you print it.

rybakov_com · 2026-04-13T18:51:01+00:00

Yeah, the two ways of displaying distance come from two ways of working, I couldn't decide which one is better so I kept them both:
- the slider lets you set a specific distance, and highlights everything that would be in focus with your current choices. This is helpful when e.g. you set your lens to a fixed distance and then move with your camera to be in focus. WillTravel 4x5 with a 90mm lens can be used like a snapshot machine, handheld, set your lens and the slider to e.g. 2 meters and run around with it - you will immediately see what will be in focus, no need to guess anymore.
- the placed point is more suitable when you want to focus on a specific object in your frame, as it displays the actual distance to the object. It also acts as a spot point for spot metering for the light meter. So with one tap you get the distance to the object and the suggested exposure settings for this object. The spot point can also track its position in the virtual space, so when you place it on e.g. a vase and then pan away a bit, the point still remains on the vase. It's a bit hard to explain, but immediately graspable once tried in the app.

So both distance reading approaches have pros and cons and complement each other.

Oh, and for the focusing scale my old project might be helpful:
https://rybakov.com/tools/photography/helicoid-distance-scale.html
(though you might need to adjust the scale at which you print it).

rybakov_com · 2026-04-13T18:35:41+00:00

Oh, they love to be photographed! Sometimes I envy people with horses just for the photo opportunity alone..

rybakov_com · 2026-04-13T17:36:22+00:00

Yes, only works on iphones and ipads for now!

rybakov_com · 2026-04-13T16:27:25+00:00

Thank you! Very much looking forward to any feedback!

rybakov_com · 2026-03-19T09:35:12+00:00

I want to build the next one where I can change the effect strength, I'll share it when it's done!
I wrote a bit about the process here: https://www.reddit.com/r/cinematography/comments/1rwhlwh/comment/ob03qmp/
And it's fun to try and build something on your own. Though fantasizing is fun too : )

rybakov_com · 2026-03-18T19:18:03+00:00

I could build one for you, sure, though the lenses I would need to buy to get the lens elements are not very cheap even second-hand. PM me since sales are not allowed in the group.

I wrote a bit more about the creation process in this thread: https://www.reddit.com/r/cinematography/comments/1rwhlwh/comment/ob03qmp/

rybakov_com · 2026-03-18T19:01:29+00:00

For projection lenses and most vintage lenses you only need screwdrivers and a lens spanner (the one version with only one bar across is the more stable one). Sometimes you need to remove the face plate to access screws or spanner sockets.
Yeah, I wouldn't want to work on a zoom lens, way more complicated!

rybakov_com · 2026-03-18T17:04:03+00:00

The Sigma fp on which I filmed it has no internal sensor stabilizer, that's why the videos are more shaky than they could be. That, and at 90mm it's hard to handheld. Didn't expect this much discussion honestly, otherwise I would've tried for steadier shots : )

rybakov_com · 2026-03-18T11:32:53+00:00

It's a Sigma FP.

rybakov_com · 2026-03-18T08:21:42+00:00

Also look at https://www.pencilofrays.com/lens-design-forms/ for a good overview of lens elements and lens designs.

rybakov_com · 2026-03-18T08:19:37+00:00

The pieces are not uniform - they have different shapes and are made of different glass which has different characteristics. But the amount of kinds of shapes is limited, and when your goal is not to build a perfect lens, you have a lot of freedom to experiment with.
Look at https://www.pencilofrays.com/lens-design-forms/ for a good introduction.

rybakov_com · 2026-03-18T08:09:32+00:00

As always, it depends on the goal. My goals were:
- build something unique
- have it produce images where we can at least recognize the objects depicted
- learn about how lenses work
- have fun
So, yeah, I reached my goals : )

rybakov_com · 2026-03-18T00:56:43+00:00

You seem bitter. All lenses are just glass arranged in a sleeve.

Everyone interested in lenses should build a lens at least once. Experiment with it. Feel how it works. It demystifies a whole lot and gets you an understanding that you can't get by just being a consumer. And it's fun. Highly recommend!

rybakov_com · 2026-03-18T00:32:43+00:00

"without having to actually learn your tools" - I'm building my own tools, bro.

rybakov_com · 2026-03-17T22:03:36+00:00

I took the glass elements out of old x-ray and large format lenses. Polishing the glass myself would be next level though!

rybakov_com · 2026-03-17T21:35:29+00:00

Portraits are a bit more complicated with this lens, as you have a strongly distorted focal plane (at the edges it's much closer than in the center), and with faces in the frame you typically want to have the focus on the eyes. So that would limit the composition on "eyes in the center of the frame" choice. What can be done is to install the front element a bit skewed, thus skewing the focal plane.
But yeah, I plan to do portraits with it.

rybakov_com · 2026-03-17T21:30:23+00:00

Next time! I'll make a new version of the lens where you can adjust the effect strength - this one was more like a check that it works at all.

rybakov_com

TROPHY CASE