Building A Professional Grade Shutter Tester

FM2 · Aug 9, 2023

ic-racer said:
I used the parts from the BOM file (Rev 3), rather than the WIKI (Rev 4). In that case, resistors locations for R1-R4 printed on the PC board would be:
R1 = 2k
R2 = 2.2k
R3 = 4.7K
R4 = 4.7K

C1 = 220uf
C2 = 470uf

View attachment 346093
Resistor

Yes, that's true of course. However, the wiki does not state what resistor belongs to R1, R2, R3 or R4. That's why I went with the *.csv file and went with the parts stated there.

ic-racer · Aug 9, 2023

Keep posting updates of your builds here. This thread can be the substitute for the lost "Discussion" forum on GitHub.

aconbere · Aug 13, 2023

@ic-racer this is another dumb question but do you know what size that little 0.091 ohm SMT resistor on the driver should be?

aconbere · Aug 17, 2023

I ended up just buying a few at a bunch of different packages, will report back.

ic-racer · Aug 17, 2023

I wasn’t sure either, the one I got from Mouser was smaller.
I made it fit with blobs of solder that you can see in the picture.

FM2 · Aug 20, 2023

aconbere said:
@ic-racer this is another dumb question but do you know what size that little 0.091 ohm SMT resistor on the driver should be?

I used these ones (0.091R), they fit pretty well: https://aliexpress.com/item/32865874154.html?

FM2 · Aug 23, 2023

FYI: Discussion section on github is back online: https://github.com/srozum/film_camera_tester/discussions

ic-racer · Aug 23, 2023

FM2 said:
FYI: Discussion section on github is back online. Well, at least parts of it: https://github.com/srozum/film_camera_tester/discussions

Thanks for the update!

aconbere · Aug 23, 2023

Amazing! These are all so useful. I wonder why they were taken down.

ic-racer · Aug 24, 2023

Found my 'build' thread in the now-recovered Discussion area here:

Documenting My Build... · srozum/film_camera_tester · Discussion #23

Just starting a discussion showing my progress. Since no parts have arrived yet, I'll start with background. Maybe many like the project as a shutter tester, but I have made many of those in the pa...

github.com

aconbere · Aug 28, 2023

Heh, feels like I'm getting close now.

But the screen reads:
"
amera Tester
Version
"

I'm going to assume that this is likely because I just ran avrdude directly against the nano and didn't use a second device as the programmer. So ... I'll work on that for now, but curious if anyone else has seen this.

ic-racer · Aug 28, 2023

I made a programmer out of an extra Nano clone. The programmer is on the right and it is programming the board on the left.
Below shows the screen that should come up if the board was flashed correctly.

ic-racer · Aug 28, 2023

Use the Arduino IDE app to load the programming software on the programmer board.
Then (with a desktop iMac) I used the "Terminal" program to run Avrdude.

The piece of yellow paper has diagrammed the connections to make the programming board. I added the capacitor and resistor per recommendation I found on the internet:

aconbere · Aug 28, 2023

Welp, when I used an ISP programmer it did in fact work correctly.

ic-racer · Aug 28, 2023

Like many projects, some things never are really done. I still need to make my flash synch cable.

FM2 · Aug 29, 2023

Just wanted to share the encoder I used since many people ran into problems with theirs. Works really well for me. I used the "15mm plum handle" version.

https://aliexpress.com/item/10000056483250.html?

FM2 · Aug 29, 2023

I got a calibration question. I don't have a lightmeter and therefore I looked for other ways to calibrate the light source. What I do have is a xrite i1 Display Pro monitor calibration device that can measure cd/m2. I switchted to K12.5 in settings and converted the EV values to cd/m2: EV13=1024cd/m2, EV 12=512cd/m2 etc. I adjusted the potentiometer of the power source until I had a linear match (currently11.6V). Is this a proper way to do it in lieu of a lightmeter?

ic-racer · Aug 29, 2023

Math looks good.

The k12.5 meter I used to calibrate mine came with a conversion table that gave EV13 as 1000 cd/m2 and EV12 as 510 cd/m2.

FM2 · Aug 30, 2023

Could it be device specific? I didn't come across those values during research and the github page also lists the values mentioned above in the table for K12.5: https://github.com/srozum/film_camera_tester/wiki/Light-Source

ic-racer · Aug 30, 2023

FM2 said:
Could it be device specific? I didn't come across those values during research and the github page also lists the values mentioned above in the table for K12.5: https://github.com/srozum/film_camera_tester/wiki/Light-Source

Yes, it is device specific (for the K value), but also probably rounding the numbers makes some differences. But your calibration seems sound.

vandergus · Aug 31, 2023

Finally got around to building my light unit. To add to LED question, here's what I bought.

Cree XHP70.2 GEN2 High Power LED in Warm White (3000-3500K), 12 V, on the 20mm circuit board.

https://www.aliexpress.us/item/2251832705760163.html?spm=a2g0o.order_list.order_list_main.22.591f1802Do46YF&gatewayAdapt=glo2usa

I used the Falken brand diffuser linked by ic-racer earlier in the thread. I ended up driving it somewhere between 11.5 and 11.9 V, can't remember the exact value. I don't have a dedicated light meter so I had to go with the law of averages and used a handful of trustworthy cameras that I had on the shelf. The calibration seems good but it isn't perfectly linear over the entire range. EV16 is maybe 1/3 to 1/2 stop too dim.

Excited to finally have such a capable camera tester on my bench, though! It really does make everything easier.

Edit: Photo of my build

ic-racer · Aug 31, 2023

Wow, looks fantastic. I like the white printing.

Some things that bother me on mine is my neck hurts looking into the viewfinder at desk level. So I'm thinking of making a stand to bring it up to eye level.
Also, the trim ring around the display cuts off the top part of the display to my view from desk level (horizontal build).

This is Sover Wong's setup. He has the tester up on a stand and there is a little shelf on which the camera can sit.

ic-racer · Aug 31, 2023

vandergus said:
The calibration seems good but it isn't perfectly linear over the entire range. EV16 is maybe 1/3 to 1/2 stop too dim.

After looking at the user's manual for a Kyoritsu tester, I see the "Film Camera Tester" has copied the same basic setup. One thing not copied is a way to adjust the linearity of the EV scale based on one's chosen LED and reference meter.

The Kyoritsu has 4 trimmers to adjust EV6,9,12 and 15 individually, whereas "Film Camera Tester" has the intensity values from EV6-16 hard coded.
With both devices, there is no getting around the fact the color temp of the lamp changes as the EV value changes. So one needs to adjust accordingly to match sensitivity of the meter's cell.

One thought would be to have a table embedded in the "Settings" file that the user could alter to adjust linearity or non-linearity of the light source to match one's 'standard' meter.

vandergus · Aug 31, 2023

I know what you mean about the having to stoop down to look through the viewfinder. I happen to have an adjustable desk and when I put it in standing position, I can sit in a chair and be at about the right level for easy viewing. It's pretty workable.

It is a bit of a shame that the light source calibration isn't more adjustable. Especially since the whole thing is essentially built around a knock off LED with no well defined specs (a truly mystifying decision, imo). It really needs to be more flexible. But I can't be too critical because, taken all together, it's really a wonderful project.

Twotone · Sep 7, 2023

Evening all,

Seems I'm pretty late to the party with this but I'm planning on taking on this build. I will say though as a precursor, my soldering is god-awful, and generally electronics aren't my strong point.

I'm likely going to need some support from a friend who is an electrical engineer but we'll see how it goes.

I greatly appreciate your updates and observations OP, as do I appreciate the comments from others who have taken this on, I'll certainly be seeking some guidance at some point from you all.

I'm planning to start ordering bits in the next few days, and then inevitably realise I'm missed a load of stuff.

Anyway - I imagine the next post on this thread will also be from me..

Thanks,
TT

Building A Professional Grade Shutter Tester

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