Photoplug - what am I doing wrong?

IanCC · Dec 5, 2023

After reading about the Photoplug shutter speed tester, with app., it sounded like it was easy to set up and use, with reasonable results, assuming you set it up correctly.
So I set up a simple rig using my Sinar Norma kit to test large format lenses. My problems is that I am not getting a second peak, so am unable to position the second blue marker To enable getting a result.

I am sure somebody out there is getting results so any info about your own set up may help me.
There is no interfering light source, my light source is directly in front of the front lens. I have removed the rear lens. The sensor is inside the bellows, so the light that hits it is the light coming in from the light source I have set up. The sensor is plugged into a 3.5mm jack adapte, which plugs into my iPad charging socket.
Any thoughts, or am I just making it all too complicated.
HELP! please.

_T_ · Dec 5, 2023

I just read a little bit about people having the same issue that you're having. Apparently at higher shutter speeds it can be difficult to find the second peak. Also, I'm not certain that the device is designed with leaf shutters in mind. It doesn't say in any of it's documentation that it is intended for that purpose, so it could be that it would be more difficult to find the peaks with a shutter like yours.

mshchem · Dec 5, 2023

So just for focal plane shutters?

jk0592 · Dec 5, 2023

No, Photoplug is not for focal plane shutters. It is for leaf shutters only.

mshchem · Dec 5, 2023

IanCC said:
After reading about the Photoplug shutter speed tester, with app., it sounded like it was easy to set up and use, with reasonable results, assuming you set it up correctly.
So I set up a simple rig using my Sinar Norma kit to test large format lenses. My problems is that I am not getting a second peak, so am unable to position the second blue marker To enable getting a result.

I am sure somebody out there is getting results so any info about your own set up may help me.
There is no interfering light source, my light source is directly in front of the front lens. I have removed the rear lens. The sensor is inside the bellows, so the light that hits it is the light coming in from the light source I have set up. The sensor is plugged into a 3.5mm jack adapte, which plugs into my iPad charging socket.
Any thoughts, or am I just making it all too complicated.
HELP! please.

If you are using light powered by AC you may be getting flicker. Try using a flashlight using a battery, or sunlight. Incandescent lights that are good and hot should be OK. AC, anything other than tungsten, even LED will flicker enough to disrupt my DSLR when shooting faster than 250th.

jk0592 · Dec 6, 2023

When using strong led flashlight, the light might be too strong for the photoplug. Using low light will help a lot.

IanCC · Dec 6, 2023

Thank you all for the replies.
My light source is a battery powered LED light, the LED is a 3V 6,000K torch light.
One thing I didn’t mention is that when I pull the connector from the iPad charge socket my music plays; as if it thinks there was a headset plugged in, could that be significant?
Ian

ChrisGalway · Dec 6, 2023

When I used a phono-lightning adaptor for my newish iPhone (which has no phono connection), I could not get the PhotoPlug to work properly. My solution was to use an old iPhone with a phono socket ... and I've never had a problem since. I use a bright LED flashlight/torch, and typically and testing lower speeds up to around 1/125th. So perhaps your phono-to-USBc adaptor is the problem?

IanCC · Dec 6, 2023

Hello Chris you may be right, however my connection is via a short phono to lightning connector, (no USB) and i've tried several different ones with no joy and same results. it is very annoying. I read somewhere that using an IR light source is best but I have not yet tried that. Has anybody reading this tried IR?

Next i'll try to contact Lukas Fritz to see if he can help.

If we can keep the thoughts coming I am sure collectively we can get to the bottom of the problem and then share a solution.
Ian

koraks · Dec 6, 2023

Are you sure your iPad detects the Photoplug as a microphone? If you plug in an actual microphone to the same lightning connector and start the Photoplug app, do you get to see sound waves that respond to environmental sound (clap a hand etc.)?

If you use the Photoplug as you've wired it up in the photo and you wave a bright light across it (you'll have to flip it past the sensor quickly, I imagine), do you see the waveform change in the Photoplug app?

I think the odds are about 90% that the problem is related to the iDevice not enabling its mic input. If you have someone nearby with an older Android phone with a regular 3.5mm jack plug, maybe you can pester them a bit and nick theirs for a few minutes and see if it works.

titrisol · Dec 6, 2023

IanCC said:
After reading about the Photoplug shutter speed tester, with app., it sounded like it was easy to set up and use, with reasonable results, assuming you set it up correctly.
So I set up a simple rig using my Sinar Norma kit to test large format lenses. My problems is that I am not getting a second peak, so am unable to position the second blue marker To enable getting a result.

I am sure somebody out there is getting results so any info about your own set up may help me.
There is no interfering light source, my light source is directly in front of the front lens. I have removed the rear lens. The sensor is inside the bellows, so the light that hits it is the light coming in from the light source I have set up. The sensor is plugged into a 3.5mm jack adapte, which plugs into my iPad charging socket.
Any thoughts, or am I just making it all too complicated.
HELP! please.

At which speeds are you having that issue?
I have used the Photoplug for a few years and I think it is reliable up to 200
After that is very hard to find the peaks
PS I see you are using it in an iPad, I kept and old iPhone 4 for my photoplug

Doremus Scudder · Dec 6, 2023

IanCC said:
Thank you all for the replies.
My light source is a battery powered LED light, the LED is a 3V 6,000K torch light.
One thing I didn’t mention is that when I pull the connector from the iPad charge socket my music plays; as if it thinks there was a headset plugged in, could that be significant?
Ian

LEDs flicker. Use a tungsten light source.

IanCC · Dec 6, 2023

I am going to follow up on the issues identified that may help me get it sorted.
Titrisol, Regarding speed, I started at 1 minute, but still only see the 1st peak, went on down to 500, then 250, same issue so stopped there. Koraks, I will try your suggestions this evening thank you all very much.
More positive things to tell tomorrow, I hope

IanCC · Dec 6, 2023

I wonder, does the type of plug make a difference to what the sensor picks up, 1, ring, 2 rings, or 3 rings?

Ian David · Dec 6, 2023

Start with the slow speeds first - my Photoplug works very well (with iPhone 12) for all speeds slower than 1/250, then it gets harder to interpret due to the lack of vertical coverage of the waveform image.
You have to zoom right in on what can initially look like a single peak to see the appropriate start and stop points for the sliders.

reddesert · Dec 6, 2023

The Photoplug uses the iPhone's microphone input to convert the light signal to an electronic pulse, so it "looks" to the iphone like a sound. You absolutely need a plug and a jack that have 4 connectors, because the 4th connection is for the microphone. The mic is the ring closest to the base of the plug, the ground is next, and the audio L and R output are the two connectors closest to the tip (which the Photoplug won't use). If you use a typical stereo plug/jack with 3 connectors, it will ground the mic and you'll see nothing.

I have a homemade photoplug (the electronics inside are not complex). It does work with iPhone 4 and 6 with a 1/8" jack. I have not tried it with a 1/8" to Lightning adapter.

The Photoplug should work with a focal plane shutter, though it will only give you one reading, so you can't measure uneven exposure (curtains moving at different speeds).

I recommend testing it at some intermediate speed like 1/15. For fast speeds with the Photoplug, it may take a little experience to separate the peaks, as the plug+mic response time brings them together. You can also test the app on a leaf shutter in sound mode without the plug; it should work ok at 1/30 and slower, but faster than that it is hard to separate the sounds of shutter opening and closing.

It would be helpful if you posted a screenshot to show what waveform you are seeing. It's really much easier to debug this kind of thing with pictures.

IanCC · Dec 7, 2023

Hello, these are the wave form I have been getting yesterday and it was the same shape for each shutter speed. After following advice and suggestions I now have different wave forms but I am “blowed” if I know where to properly position the blue marker dot.
Perseverance is the key, as it is important. If we can measure something, we can control it.
I’ll double check I wasn’t dreaming them, then post the photos of the different wave f

orms later today or tomorrow.
Note, in the photos, I have shifted the dots out of the way so the wave shape is visible.

titrisol · Dec 7, 2023

your wave form looks really strange
This is what I got
Tthen you move the blue balls to the beginning of each wave

IanCC · Dec 8, 2023

Hello, do you have a photo of your set up, and what light source did you use? Do you take the measurements in the dark? Some of my wave forms taken since stripping my rig down and starting again. But I am still not happy but it is a lot better. Looking at the 1:100 , where do I position the dots?
It’s time for me to review all that I have read here and summarise. I will then test my next lens.

titrisol · Dec 8, 2023

I use a flashlight on the backside and the photoplug on the front side
I have used the otherway as well, but it is easier to balance the flashlight in the film chamber for 35mm and 120 film cameras
In your case a flat panel can fill the back of the camera and illuminate towards the front of the lens
I use a relatively dark spot where the flashlight signal will be way above bkg noise

The manual says to chose be beginning of each peak, zooming in you can see something like this

IanCC · Dec 11, 2023

With everybody’s help and some online reading I have finally got a set up that works, thank you. I have made notes of my process, and equipment used, which I may post if anybody is interested?

My next issue is, now that I can make adjustments to f-stops to compensate for shutter speed errors, how do I combine these with the ‘bellows factor’; for extended bellows draw? Do I add them together or do I integrate them, ie. Use the highest adjustment factor? Maybe this is the subject of a new thread?
Ian

koraks · Dec 11, 2023

IanCC said:
I have made notes of my process, and equipment used, which I may post if anybody is interested?

Yes, please! There's bound to be someone in the future who will benefit from your experience.

IanCC said:
how do I combine these with the ‘bellows factor’; for extended bellows draw? Do I add them together or do I integrate them, ie. Use the highest adjustment factor? Maybe this is the subject of a new thread?

Correction factors are added on top of each other.

Say your shutter is off by 2/3 of a stop, you have a 1 1/3 stop bellows correction factor, you're using a green filter that eats up 2/3 of a stop and you have a polarizer fitted that chops off another stop. Your total correction factor would become 2/3 (shutter) + 1 1/3 (bellows) + 2/3 (green filter) + 1 (polarizer) = 3 2/3 stop. An initially measured shutter speed of 1 second could be corrected to ca. 13 seconds instead, or you could open up 3 2/3 of a stop (e.g. going from f/22 to ca. f/5) to keep the same shutter speed.

Don't forget about possible reciprocity failure corrections with long exposure times, especially on B&W film.

titrisol · Jan 23, 2024

IanCC said:
With everybody’s help and some online reading I have finally got a set up that worksView attachment 356308, thank you. I have made notes of my process, and equipment used, which I may post if anybody is interested?

My next issue is, now that I can make adjustments to f-stops to compensate for shutter speed errors, how do I combine these with the ‘bellows factor’; for extended bellows draw? Do I add them together or do I integrate them, ie. Use the highest adjustment factor? Maybe this is the subject of a new thread?
Ian

Did you post this?

IanCC · Jan 24, 2024

Photoplug - what am I doing wrong?

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