9 replies to this topic

[Drew]

Using the 5D1-3 full frame DSLRs means suffering X-sync speeds of 1/200, which limits shots like sunballs and even action shots. This is because of the TTL circuitry forcing the sync to a max of 1/200. Using a bit of ingenuity (and this guide from Stephen Frink), I was able to push past 1/200 to use 1/250 and higher. In my previous review of the 5D2, I mentioned how using 1/320 would create a black band at the bottom of the image. However, going through my travel drives to clear the junk files a few months back, I noticed I had a few clean 1/320 shots in my various experiments on testing strobes and filters. These images were junked because they were bad. However it showed me how to possibly get 1/320 from my 5D2 and maybe even other cameras.

1/320 f11 ISO200

The left side is the "bottom" of the image so it's hard to see if the shutter affected this pic.

The above shot was the first pic I saw with 1/320. I thought it was an EXIF error but then I checked other shots in the series and they were all 1/320. Comparing it with my test shots on the review (below), it was clear that there was something different.

1/320 f7 ISO100

Turns out the different is the angle in which the camera is pointing. In all of the 1/320 shots that were without bands, the camera was in portrait view and facing up to the sun. It seems gravity slows the shutter and mirror flip enough so at 1/320, it managed to avoid the black band of the shutter or mirror.

Excited with this discovery, but wanting to verify, I called upon other Canon users. A friend using a 1D4 with manual strobe firing also noticed less of a band when using 1/320 or 1/500 and shooting vertically on his camera. The band is there but less so. He didn't have any upward facing pics to check.

I'd wanted to test this in South Africa during the Ocean Safari, but I got busy and whenever I got in the water, it was on action so I never remembered to do so. However, I shoot 1/250 as standard on baitballs with the 5D and that wasn't a problem even pointing down:

1/250 f8 ISO640

However, Mark Van Coller (MJvC) couldn't get his camera to sync @ 1/250 even, without a black band (minor one at the bottom of the image) in his Subal with Sea & Sea 250 and Ikelite strobes. The housings I tested and worked with 1/250 and 1/320 were Aquatica, Seacam and Sea&Sea, with Hartenberger 250 and Z240 strobes.

It seems it's possible but I haven't solved the riddle yet other than to shoot vertically and point upwards. Since I'm going to be dry (and housing-less!) until next month, I was hoping to get WP members to go out and experiment and report back! This could possibly work with a bit of experimentation.

1/320 f11 ISO200 Note that there is a line of darkness at the bottom of the image.

I'm not sure if it was bad light positioning or the effect of the shutter/mirror

1/320 f11 ISO100

The left side is the "bottom" of the image so it's hard to see if the shutter affected this pic.

[escape]

Interesting. I just tried dry test 5dmk3 and z240 (full power, trigger by optical led) in dark room, I got almost same amount of banding in any angle.
I think the first and last your images showing less dark line because that area doesn't lit by strobe?

[Drew]

Eun Jae, have you tried with sync cables? I think an electrical signal may be easier to sync (or miss-sync) than the optical cords where there's more processing involved?

I agree that the images aren't the best to test this theory out but then again, the output is very usable without cropping. A friend who tested it at 1/400 claims no black band at all but no strobe lighting on a portion of the pic, which makes it seem that the flash is actually flashing before the shutter is fully opened vs closing as I initially thought. Try exposing to the room and see if there's a portion of the room unlit by the strobes.

[escape]

Drew, I tested with both but I got same size of black bar.
Anyway I understand your approach to use faster then 1/200sec with ambient light which I should try underwater (if I understand correctly).
btw, I found these on Strobist.

http://www.flickr.co...N00/2730231807/
http://strobist.blog...t-50-years.html

[Drew]

Yes well that would seem to correlate to my findings.

I think exposing to ambient light -1 EC and positioning subject in the upper 2/3rds of the frame will help. I'm not sure why some cameras have the black band (I don't think it's underexposed) and others don't. I'll have to check other cameras.

[Alastair]

i have noticed sometimes on my D90 that i can get 250 out of it and occasionally higher but i have never been able to figure out how to repeat the effect.....

[escape]

i have noticed sometimes on my D90 that i can get 250 out of it and occasionally higher but i have never been able to figure out how to repeat the effect.....

My Canon 7D do fine with 1/320 (advertised 1/250), I guess ff is harder because of mirror size.

Edited by escape, 16 August 2012 - 01:26 AM.

[buddy]

maybe a bit off-topic and not so usable for underwater but still interesting:

Today, the same is possible on using studio strobes e.g. outdoors with sync speed up to 1/8'000 of a sec !
The trick here is to use a strobe with a relative long burning time and to release the strobe before the shutter starts to run at the very fast shutter speed. Off course, by this method you will loose power since all the pixels are getting flash light only in a fraction of time. But it actually works. For example shooting a portraiture outdoor against the full sun in the background at 1/8000 speed and aperture f/2.8 (and without the necessity of using any ND filters)...

It is actually called Hypersync Automation by this producer:
http://www.pocketwiz...persync_fpsync/

[Drew]

Juerg
I have the pocket wizards and the control of HSS is one thing I'm confused why housing/strobe manufacturers haven't instituted such boards on their products. Seems pretty straight forward.

[Stewart L. Sy]

My 7D shoots up to 1/320th as well with no bands in verticals, but I get them in horizontal shots. I was using the new YS-D1's with Electrical Cords.

S.