Shutter speed tester - am I thinking about this right

[CamB]

I've set up my DSLR pointing through a Fed2 and compared:

- DSLR shutter speed, Fed on bulb
- Fed shutter speed, DSLR on bulb

I've taken some care to try and limit the amount of light that gets around the edge of the DSLR lens by shrouded it (not shown). Assume I got that right.



This is the result on 1/500 and 1/60. The left hand picture is a control (just DSLR), the 2nd with the Fed on bulb and the 3rd with the Fed being the shutter. It looks like 1/500 is a little slow and 1/60 a little fast. I'm ok with that as a compromise unless anyone can suggest what combination of changing the tension of each of the 1st and 2nd curtain will fix both...



Thoughts on whether this is accurate / sensible? Would it also identify uneven exposure due to different 1st and 2nd curtain tension?

(edit - I should add that I have a photoplug and it agrees - perhaps more saying that 1/60 is ok and 1/500 slow. I am hoping to also identify any curtain tension related problems by this method, plus I guess it could theoretically test up to much higher speeds)

 

[Scrambler]

I'd trust Shutter-Speed and the photoplug over the dslr. Who said the dslr was correct? It will simply be consistent.

You have a dslr focal plane shutter but the FED functions as an in-front of the lens shutter. The system will not detect problems with capping etc. Try taking a photo with 1/2 the front element of the dslr lens obstructed and see what I mean.

 

[CamB]

I agree that the test is only as good as the DSLR (actually mirrorless in my case - an Olympus OMD if that's not clear from the picture, but it shouldn't matter).

I am not sure I understand where you're coming from on the second point. The way I think about (and recognising I don't know what I am talking about), the DSLR isn't a shutter at all - it's just a (pre focused) sensor?

 

[charjohncarter]

How do you know the f stop is correct? Even if you have super testing equipment for shutters, what if the aperture is off. As long as it is correct in the case of FP shutters from right to left or maybe some are vice versa, the final product will only be good if the f stop is consistent, the throw a metering error in there and ????? marks.

 

[CamB]

Do you mean, why am I worried about iany of this if there's potential error in the f stop and / or metering when I take photos .. Or is it about the control camera / tester?

In the case of the latter, for arguments sake let's assume that the Olympus has an accurate shutter speed and f stops on the lens being used. I'm not convinced that the f stop needs to be accurate (the point is to compare exposure between the DSLR shutter and the FED).

On the former - if I can have an accurate shutter speed I'd like to have it. Enough can go wrong, what with the need to meter, compose, focus, decisive moment, develop, scan or print and all that.

 

[Ronald M]

Calumet Shutter checker. Oh they are gone.

The use a TV screen. Oh now we use digital.

How about a phonograph record. Opps, that is 2 or three generations back too.

Then just use 6 or 8 exposures and change the F stop and look at the density. Keep away from full open and the smallest stop. That is what I did before I had the Calumet.



Generally you do a CLA before screwing with the tensions. DAG is the only person I ever found who could get every speed correct. Others only got close.

 

[rick oleson]

You can pick up a CRT television for about 5 bucks at a thrift store. I keep one in my camera room, just to have it for a shutter tester. And I can watch old DVDs on it while I work.....

🙂=

 

[Dwig]

You can pick up a CRT television for about 5 bucks at a thrift store. I keep one in my camera room, just to have it for a shutter tester. And I can watch old DVDs on it while I work.....

🙂=

If you go this route, go for a B&W TV and not color. You'll also need a stable accurate TV signal, which since the airwaves are now digital, may be hard find.

Old style B&W TVs are good for shutter speeds over about 1/60th but poor for slower speeds. An old accurate turntable is also good for the slower speeds but difficult to use accurately for very fast speeds.

 

[rick oleson]

You don't actually need a signal at all, if you can get a screen full of snow that works fine. Even better is the blank blue screen that I get from my DVD player when there's no disc in it. And a CRT works the same whether it's color or B&W; mine happens to be color.
http://rick_oleson.tripod.com/index-135.html

 

[bence8810]

+1 for Shutter-speed and the Photoplug from eBay. All in all this $30USD combo will solve all your trouble. It isn't without its quirks but it's reasonably accurate and definitely cheap! Oh, did I mention tiny too? About the size of a headphone jack sticking out of your iPhone...

Ben

 

[RichC]

Using a digital camera as a shutter speed tester works fine. Quick, easy and accurate. I use one to check all my manual cameras. My Mamiya 645, for example, was way off but now exposes perfectly.

Ignore those suggesting expensive or unnecessary shutter testers, or obsolete, clunky methods like using old TVs. 🙄

All you need is a dSLR and stuff lying around at home - as you've shown. I add two books with dark covers, a bit of white paper, a black T-shirt, a desk lamp and some Blu-Tack! This link explains the dSLR method in detail for those interested: http://vapour-trail.blogspot.co.uk/2009/04/how-to-test-calibrate-manual-slr.html

dSLRs not trustworthy? 🙄 With modern quality control and technology, the shutter speeds in a dSLR will be accurate unless it's broken or knackered. Anyway, being digital, you can take a photo and instantly see if the exposure is off!

 

[Sparrow]

... you can use the refresh rate of an old CRT screen

 

[Pherdinand]

it's a good trick - thanks.

 

[CamB]

Thanks for the responses - its good to see ongoing discussion and shared viewpoints. RichC - you're way ahead of me (I searched too...)

On the CRT, I just want to avoid having another piece of "stuff" around. It doesn't help that its quite a bulky bit of gear.

+1 for Shutter-speed and the Photoplug from eBay. All in all this $30USD combo will solve all your trouble. It isn't without its quirks but it's reasonably accurate and definitely cheap! Oh, did I mention tiny too? About the size of a headphone jack sticking out of your iPhone...

Ben

I have a photoplug - I think its a great piece of kit, convenient to use and very good value (and absolutely recommend it in addition to what I've been tinkering with), however:

- it's speed limited to 1/500 (and see note below on 1/250 and 1/500). I have cameras with up to 1/8000 (Nikon F-801s, or an FE2 and FM2 at 1/4000). I haven't tried with the digital camera method to see if above 1/1000 is accurate, but it suggests my M4-2, which I have tried at 1/1000, is pretty close

- while the photoplug works great (in my experience) at up to about 1/125 or 1/250, I think it starts having limitations beyond that. It might be user error (eg where I am positioning the photoplug or the light I am using), but I consistently have slower than expected speeds reported for 1/250 (slightly) and 1/500 (moderately - eg 1/2-1/3 stop). While it could be the cameras, its at least somewhat unlikely that there is a similar magnitude issue with a Leica, two good condition Nikons (FE2 and FM2n) and 3x Ricoh with the same shutter. Plus 5 mins on the internet corroborates this. I also see the same magnitude of differential between what the photoplug says the FED2 1/500 is and what the digital camera method suggests (although in both cases its slow). You might say "so what", but given a lot of people spend a lot of money on lenses with wider apertures where higher shutter speeds are convenient (in good light or at EI400) ... I think its helpful to know that fast speeds are good

- I think that the method I have set out above would potentially identify uneven exposure (although I am unwilling to deliberately tweak the FED to find out, as its going well at the moment)

 

[bence8810]

Hi there,

I see, so you've actually found some inaccuracies with the Photo plug. Might worth to try and email the guy who makes them?

I don't have fast cameras, the highest speed I have on any given camera is 1/1000 and I hardly ever use that speed.

I just used the photoplug to adjust my Mamiya M645 1000S and it worked great. Having said that, Mamiya suggests to tune the 1/60th to perfection and the rest will fall into place. I did that and I also noticed it was slower on 1/500 and 1/1000 but I didn't care much as I shoot black and white only and a little deviation won't show. From what you say though, it might just be that the camera is perfect and the Photoplug is what measured it inaccurately.

What about professional testers? I have seen one in some forum post in the past, it was a device also using some optical sensor but It did seem like a pretty big piece of equipment.

I am happy with the Photoplug and my pictures do come out right on spot as I meter but I don't have experience with the higher speeds and more sensitive environments like Slide film etc.

Ben

 

[CamB]

To be honest I'm not worried about it - there's just as much chance that its user error (me) than the photoplug and even **if** (not saying it is for certain) its 1/3 or 1/2 stop out I am not even close to that accurate with metering.

Its more about the ability to test higher speeds.

 

[bence8810]

To be honest I'm not worried about it - there's just as much chance that its user error (me) than the photoplug and even **if** (not saying it is for certain) its 1/3 or 1/2 stop out I am not even close to that accurate with metering.

Its more about the ability to test higher speeds.

Got it! That is indeed a valid point, I didn't know the Photoplug was limited to 1/500 as I don't really test above that...

It does make sense, however, since the reading is done by a human (you and I for instance) and we need to set a start / end point using the wave that is captured as a representation of the light as seen by the sensor. This will obviously limit the accuracy and the higher the speed, the lower the chance we can distinguish the "bad waves" from the "good waves".

Good luck with the hunt!
Your DSLR test looks very scientific.
Ben