Shutter-Speed-Tester for the iPhone

[lukas_fritz]

<p>Hi,<br>

first of all I hope it is ok to post something like this and it's in the right forum..<br>

I know, actually advertising is not allowed, but I think this could be very useful for one or two.<br>

I wrote an App for the iPhone that allows you to measure the shutter-speed of a camera. This is very useful because often the shutters of old cameras are quite inaccurate.<br>

<a href="https://itunes.apple.com/us/app/shutter-speed/id560154244?l=de&ls=1&mt=8">https://itunes.apple.com/us/app/shutter-speed/id560154244?l=de&ls=1&mt=8</a><br>

The App uses an acoustic measuring method to determine the shutter speed. You record the shutter-release-sound and the App displays the waveform of this sound. The opening and closing of the shutter can be detected by two peaks in the signal. <br>

<img src="http://www.echolot-online.de/Shutter/Shutter_Speed_Lomo_small.jpg" alt="" /> <br>

Additionally, there is an "extension" to the App: A small phototransistor-plug that you can connect to the iPhone. With it, you can measure the actual light that passes trough the camera, instead of sound. This gives very accurate measurements. <br>

<img src="http://www.echolot-online.de/Shutter/aufbau.jpg" alt="" /><br>

Would be glad to see some comments about this :)<br />If postings like this are not welcome here I will remove it of course. <br>

Best,<br>

Lukas</p>

[chansonbleu]

<p>Lukas,</p>

<p>That looks like a great idea. Now one can check shutter speeds on classics when perusing flea markets and yard sales.</p>

[fran_ois_pottier]

<p>It will probably be another twenty years before I buy a mobile phone,<br>

but this sounds very cool :-)<br>

Thanks for posting.</p>

 

[tanjyhhern5]

<p>Great idea! Now if only it was free...</p>

[jim_bielecki1]

<p>You can't afford $3.00?</p>

[Niels - NHSN]

Lucas, where do you buy the phototransistor plug?

[lukas_fritz]

<p>Hi Niels, I constructed and built this plug myself. I built several of them, so if you are interested you can purchase one from me ($16). Just send me an email: lukasfritz@gmx.net</p>

[Jon_Rogers1]

<p>Great idea, but a couple of questions:</p>

<ol>

<li>Any thoughts for an Android app?</li>

<li>Can you not use the camera on the device as an optical sensor, rather than a separate plug-in device?</li>

</ol>

 

[andylynn]

<p>That's cool. I'll have to try this. I might need one of those optical sensors. I do some eBaying and being able to say "I've tested the shutter with a digital timer and it's it's accurate within 1/3 stop..." would be useful.</p>

[Gus Lazzari]

<p>iPhones are simply amazing !</p>

<p>The <a href="http://www.kenrockwell.com/apple/iphone-5/sample-images.htm">images are incredible</a> (<em><<< Click</em> for iPhone 5 samples), the light meter apps are wonderful, and now as a clever basic speed tester; it just keeps getting better.<br /> You have to just love capitalist, unimpeded business...</p>

[gene m]

<p>What's an iPhone ?</p>

[andylynn]

<p>It's what the kids are using now instead of Brownies.</p>

[lukas_fritz]

<p>Thanks for the replies.<br>

@Jon: I'm sorry, but there won't be an android version, because this would imply reinventing the App from the ground.<br>

You can't use the camera as a sensor, because it is to slow (30fps, so the camera sensor is refreshed only every 1/30 second).</p>

<p> </p>

[lukas_fritz]

<p>Here's a screenshot of a measurement taken with the phototransistor-plug of the 1/125s of my Lomo Lubitel: <br>

<img src="http://www.echolot-online.de/Shutter/4.jpg" alt="" /></p>

<p>As you can see, the peaks in the signal are clearly visible and easy to identify. The Lubitel deviates 2/3 f-stops from the target value, a photo taken with this setting would be fairly overexposed !</p>

[tony_lockerbie]

<p>Excellent app, bought one for my ipad...works well...which is more than I can say for most of my leaf shutters!</p>

[brendan_odonohue]

How accurate is the acoustic measurement vs the optical

measurement?

[q.g._de_bakker]

Care has to be taken interpreting what peaks in the graph represent; what peak is the opening of the shutter (and not some other sound made by the entire shutter release mechanism) and what peak is the one of the thing slamming shut (the first photo shows how it can be difficult to identify the event among the 'noise')?<br>And you need to consider shutter efficiency as well, especially with central shutters.<br>The photoresistor method wil be more reliable.

[steve_mareno1]

<p>Looks similar to the tester I bought years ago on fleabay for small money. Mine is old fashioned, runs on the free software Audacity, and has a cord that you have to plug into your PC. Works a treat, and has DEFINITELY improved my exposures. Can't tell you how many shutters I've had that sounded right, only to find that they were way off. Saved me a lot of money on CLAs too. Once you know what a shutter is really firing at, you simply meter accordingly, and get spot on exposures. As always, your success will be measured by how accurately you measure the spikes on the graph, but consistency comes pretty quickly. I like the one shown here because it's so small and portable. Good job.</p>

<p>I'm envious of your Lubitel. Always wanted one, but can't seem to find a US seller. My days of buying from Russia/Ukraine etc are mercifully behind me.</p>

[lukas_fritz]

<p>@Brendan, this depends on the camera you are using. In general I can say that cameras with leaf-shutters work very well even at faster speeds. Of course, the measurement get's more inaccurate the faster the speed is. Speeds up to 1/60 work very nice with the acoustic measurement on almost every camera with leaf shutter, the faster times depend on the camera you are using.<br>

Cameras with focal-plane shutter like SLRs only give decent results up to the 1/30 or 1/60, because the sound generated by the complex mechanics inside the camera makes it hard to identify between which peaks you have to measure.<br>

With the phototransistor-Plug, measurements of both leaf- and focal-plane-shutters work very accurate all the way up to the fast speeds like 1/500 !<br>

@steve: thanks, thats exactly what the app is intended for: Improving your exposures and saving money from over- or underexposed film. <br>

The Lubitel is a nice camera indeed. Made my first steps into MF with it :)</p>

[rod_larson]

<p>Tried it on my ipad. It starts recording and won't stop. Nothing is displayed and everything just<br>

locks up. Have to go back to the main screen in order to get back to the app. Can't set<br>

shutter speed either.</p>

[lukas_fritz]

Oh, I'm sorry to hear that. Have you tried stopping the record manually by pressing the record button or do you just wait

until the red bar reached the end ? I will try to fix this problem as fast as possible.

[rod_larson]

<p>Lukas,<br>

Yes, I can stop it before the bar reaches the end and it then displays the measurement.<br>

Also sometimes when I select the app it shows "Shutter" and "Speed" where the " Take a<br>

Measurement" and "Camera Management" buttons are and it locks up again until the app<br>

automatically deselects itself. The ipad has ios6.1.3 software.</p>

[lukas_fritz]

<p>Thanks Rod, I found and solved the problem. An Update is on the way :)</p>

[rick_schuster]

<p>Nice app, Lukas. It's about the same as using Audacity on my mac to measure by sound, but it's very convenient to have it on my iphone. Seems to work fairly well. With a phototransistor plugged into the headphone jack to measure the actual light, it would be great. Can I just solder the leads of a phototransistor to an audio plug, or is it a little more complicated than that?<br>

Thanks for making this app -- I hope it sells well.<br>

It looks like it could use some improvement, though. It freezes up on my iphone if I let the recording go past 3 seconds. Then I have to restart it twice to get it working again. Why the 3-second limit for recording?<br>

Some other suggestions to improve it:<br>

1) it would be nice to have the option to select the targeted shutter speed on the record screen (before you record it).<br>

2) it would be nice to be able to select the targeted shutter speed via a simple on-screen dial instead of having the click the 1/1 to go to another screen, dial it to your speed, and click 'done' to go back. <br>

Also, I don't think the shutter speeds would have to be split into two separate dials for 'new' and 'old'. One dial containing all the shutter speeds would be simpler to use. If I want 1/4, I can select that; if I want 1/5, I can select that -- without having to decide if it's a 'new' or 'old' shutter speed.<br>

I'm not meaning to be critical, as I'm grateful that you made this app. Just want to help you improve it.<br>

Rick</p>

[rod_larson]

<p>Thanks, Lukas. I have been able to play around with it a little and it looks interesting.</p>