High speed flash synch with the D70

I have been experimenting with high speed flash synch with the D70. Using a Subal housing.

My findings are:

When there is a strobe attached to the camera (and the camera knows that it is there) then the shutter speed cannot be set at greater than 1/500th. If you turn the rear control dial it refuses to increase beyond 1/500th.

However if the camera doesn't think that the strobe is there. And the easiest way to duplicate this is to turn the strobe off (or block some contacts). Then it will fire the strobe at faster shutter speeds. (My Subtronics keep their charge in the capacitors after they turn off still fire after they have been switched off - I just turn it on between shots to recharge the capacitors).

I do not get any appreciable fall off in strobe power with the subtronics until I increase the shutter speeds to greater than 1/4000th - which drops off until at 1/8000th I hardly get any strobe light. These high values compared with what Herb has reported for other strobes may be caused because I was using the strobe at 1/16th power?

I'll get it in the pool this afternoon as post some tests later.

Alex

I do not get any appreciable fall off in strobe power with the subtronics until I increase the shutter speeds to greater than 1/4000th - which drops off until at 1/8000th I hardly get any strobe light. These high values compared with what Herb has reported for other strobes may be caused because I was using the strobe at 1/16th power?

Yes. Shooting at 1/16 power is the reason. To maintain a consistant color temperture the output rate of strobes are kept constant. Total output is proportional to duration. Based on your results above exposure falloff would begin between 1/250 and 1/500 had you been shooting full power.

Two questions, one for Alex, one for Herb.

Alex, you're saying that something needs to be done to 'fool' the camera into thinking no strobe is attached? My impression from Starbucks shot at 1/2000 was, it was taken without any special adjustments.

Herb, of course I'm not uderstanding your formula but, could you calculate the max shutter for 1/2 and 3/4 power?

Thanks,

Rand

Herb, I meant for the Inons' if that wasn't clear.

Rand

Alex, you're saying that something needs to be done to 'fool' the camera into thinking no strobe is attached? My impression from Starbucks shot at 1/2000 was, it was taken without any special adjustments.  

Not Alex (obviously, for a number of reasons.. ) but yes, this was why when I first tried to get higher than 1/200, I couldn't. THe screen on the back showed, e.g.. 1/1000, but the ev in the viewfinder showed 1/200, confirmed in exif data.

The hot shoe has to be modified so that it still fires the strobe, but the camera I guess is fooled into thinking it's not attached, so the max strobe sync speed is not implicated...... I believe this is done by altering the hot shoe pins

Chris

Rand, My best estimate for full power for the Z220 is 1/500, so 1/666 for 3/4 power and 1/1000 for 1/2 power.

I'll take a shot at your question for Alex. My Canon does not seem to "see" the Z220; I retain complete freedom to set the shutter speed with it connected and turned on. Chris has reported that's not the case with his YS90DX. It looks like whatever signal the camera looks for to determine the presence of a strobe is not transmitted by the Z220.

I did a similar test on the S2, and had the same result. I used an old Sunpack strobe (predating the 5 pin hotshoe) and was able to fire the strobe at any shuuter speed. As soon as a modern strobe was connected, I was right back to the 1/125 camera limitation.

On the S2, the shutter speed display increases, but the display flashes, and the actual shutter speed stays at 1/125.

In the case of the S2 this is of course a moot point, as the mechanical shutter blocks the sensor at any speed over 1/180.

btw, on the S2, with 5 pins connected, the camera DOES sense the Z220, and limits use to 1/125. As far as I know, Blake (at Aquatica) can wire the bulkheads in a number of different configurations. The 3 wire hookup (non TTL) might act the way Herb is describing.

Why high speed underwater? One rarely shoots greater than 125th.

Joe, Rand is the Sunburst God, and is used to shooting at 1/1000.

You know how those old guys are... don't want to change!

Thanks Herb, 1/1000 @ 1/2 power sounds just right for the CF/WA I've been doing although things may change a bit.

As for making modifications to the contacts...

Here's a quote from Karl regarding the shot Starbuck took at 1/2000:

"My experience underwater with the D70's has been rather limited to date, but I haven't noticed anything....as long as I'm shooting manual, I can pick strobe speeds well beyond 1/500....1/2000 is as high as I've ever tried and it worked"

http://www.wetpixel.com/PNphpBB2-viewtopic...ic-t-6011.phtml

Karl lists DS125's for his strobes not sure for Starbuck but neither mention doing any type mod for the flash. Guess I'll be checking that out soon enough.

Rand

"Based on your results above exposure falloff would begin between 1/250 and 1/500 had you been shooting full power. "

Not to belabor my previous post, but the above comment by a list member says it all. I have been shooting CFWA for 25 years and have never needed more than 250th to capture the sun rays. To me, it seems like some are simply trying to see what they can get away with in terms of pushing the camera/strobe limits without worrying what the picture will actually yield. I don't believe the human eye would be able to tell the difference between a 250th sync strobe fill and a 2000th strobe fill, even if you blew it up into a 20 by 30.

So I am again saying that I simply do not understand why all the testing is going on. But maybe I have a piece of apple pie missing. I like it but need all the good stuff like whipped cream and cinnamon. Sometimes I don't have that lovin and I walk away shaking my head.

Joe.

So I am again saying that I simply do not understand why all the testing is going on. But maybe I have a piece of apple pie missing. I like it but need all the good stuff like whipped cream and cinnamon. Sometimes I don't have that lovin and I walk away shaking my head

Now that's funny!!!!

Anyway, my take would be the lack of dynamic range in the digital cameras. While your film camera could catch a nice sunball shot it would blow out a digicam.....1/1000 allows rand to shoot into the sun (more or less) without blowing out the whites or trying to line the sun up behind a gorgonian.

I also don't think you necessarily need 1/1000 to get rays, I've gotten them much lower, including 1/250, but it depends on the water conditions.

Chris

Hey Guys-

there was no modifcation to my d70 and ds125s. I was able to set shutter speed over 1/2000 and still fire strobes.. that is unless the POP UP FLASH is UP!! Then, you will not get anything over 1/500 .

If you have an IKE housing the upper left lever arm will activate the flash button..this is pretty easy to do...accidently...

UWphotonewbie figured this out and I will be using foam and a duct tape to hold down whilst swimming with the Whale Sharks next week... Hope to have some pictures for ya'll real soon..

M.

"Based on your results above exposure falloff would begin between 1/250 and 1/500 had you been shooting full power. "

 

Not to belabor my previous post, but the above comment by a list member says it all.  I have been shooting CFWA for 25 years and have never needed more than 250th to capture the sun rays. To me, it seems like some are simply trying to see what they can get away with in terms of pushing the camera/strobe limits without worrying what the picture will actually yield.  I don't believe the human eye would be able to tell the difference between a 250th sync strobe fill and a 2000th strobe fill, even if you blew it up into a 20 by 30.

 

So I am again saying that I simply do not understand why all the testing is going on.  But maybe I have a piece of apple pie missing.  I like it but need all the good stuff like whipped cream and cinnamon.  Sometimes I don't have that lovin and I walk away shaking my head.

 

Joe.

Chris is right. Digital sensors are subject to clipping which will ruin a shot while the slides tend to fad from blue to white a little better. Another factor is that the D70 has minimum ISO 200, so Rand will have to shoot as twice the speed to get the same exposure limit as a sensor at ISO 100.

This is an interesting topic. And I am not in a position to comment expertly on digital since I am new to digi but old to film. I totally agree that the dynamic range is best captured with white light from the highest shutter speed you can use.

First, I want to say that I am in no way knocking this test. In fact, I am soaking up any help offered as this list is a useful tool to learn, and I am in a position to learn as much as I can absorbe and as much as you skilled people can offer.

I have shot some sunburst pics with my D100 with a CFWA emphasis and was not liking the results, so I dumped them (meaning I have nothing to show my point). But here are a few pics I shot with high speed. The first two plane shots are no flash but at 2500th while panning. I think planes land somewhere about 180-200 miles per hour. Without flash, I believe this supports your suggestion. The sky was bright and my first few shots were blown out. Only high shutter speed allowed me to capture the pics, so I definately agree with Rans feedback.

However, the humming bird was shot with 3000th of a second with manual flash, so the 500th idea is hard to swallow since I'd have a line down the frame if that were the case.

The point being this: Dynamic range may be a factor of sync. But from my 'short' experience in digital, I have not found a need to shoot higher than 125. Maybe 250, but 2000? Is the issue because you are trying to duplicate the performance of film (and not have to do much post processing) or because Photoshop is a tool you don't want to rely on?

Again, this is a forum of digital learning and I am wanting to learn. I am not saying anyone here is wrong, only that I need to learn what is right.

Thank you for the feedback. It is really appreciated.

Joe

The point being this: Dynamic range may be a factor of sync.  But from my 'short' experience in digital, I have not found a need to shoot higher than 125.  Maybe 250, but 2000? Is the issue because you are trying to duplicate the performance of film (and not have to do much post processing) or because Photoshop is a tool you don't want to rely on?

Dynamic range does not depend on sync. It's the ratio of the highest exposure and noise level. High sync speed allows high shutter speed when flash is use. High shutter speed reduces the brightness of background subjects, usually the sun, which would otherwise be clipped.

Hi kelpfish.

I'm glad you're interested in this, my favorite subject. LOL! Well, maybe I just spend too much time trying to get these type shots. But it's fun and that's what counts.

I've been shooting U/W for 2 1/2 years with a digital camera. No previous photography experience but really got bit when I started to take pics while diving.

Anyway, one of the big knocks against digital cameras has been the inability to handle sunballs. As Herb mentioned, dynamic range issues. So I took up the challenge so to speak with my Oly 5050 and started working on shooting sunballs. Now, I distinguish between sunballs and rays. Two different things in my mind.

Most digital images(Not all, especially from Dslrs) shot with the sun in them looked pretty bad. See my first photo. Shot a f6.3 @ 1/400. A fairly fast speed in your past life. :wink:

So, I just started experimenting and asking questions, getting others thoughts on shooting good sunballs. Through trial and error, I finally arrived at what I considered 'acceptable' images with the sun in them. The key really, is to obscure the sun with something to soften the ball in the middle. But, I've even gotten a few nice un-obscured sunballs, image #2. The other key was hitting a shutter speed of 1/1000 with an aperture of 6.3. And putting a turtle or soft-coral in the ball, see #3.

I recently purchased a D70 and am awaiting the housing for it. The little buzz that your seeing reflected in the posts here, have to do with the fact, and I nor anyone else realized, that unlike the other Digital Dslr's, the D70 has an electronic shutter that will allow strobe fill at the higher shutter speeds. Up to 2000 at least, which I agree is overkill for U/W use.

So, I may find that with the increased dynamic range of the D70, that this is all moot and I may get the great results at lower shutter speeds. But, it's nice to see that it's possible and who knows what may come of it.

Don't know if you've seen this thread but there's more pics and discussion about shooting sunbursts:

http://www.wetpixel.com/PNphpBB2-viewtopic...ic-t-5692.phtml

Rand

I hate to bring this up as i am most likely wrong but as i have yet to really shoot with my brand new D70 (4 days) BUT...What is the highest listed synch speed for the D70?

i have shot with the Nikonos for years, i know that i could set my shutter speed to 1000th of a sec with my strobes on and get synch. However, i was not actually getting 1000th/sec synch i was only getting 90th/sec synch as the camera could not synch higher than that and would over ride the manual setting and give only 90th anyway.

SO, are you guys sure that you are actually synching these extremely high shutter speeds?

Or is the camera over riding it and actually only shooting at the listed highest synch speed and fooling you as opposed to vice versa?

I personally have no idea but would love to know.

ps Randapex, diffs between #1 and #2 seems to me to be the time of day rather than shutter speed. #1 looks to be more in the middle of the day as opposed to #2 which looks early morning or late afternoon. Stronger light after 9 am really overexposes high shutter speeds (250 with film) much more than earlier. If you want good sunballs during middle of day you must obscure with something even at 250th. However, early and late in the day this is not so important, hence your nice sunball in photo #2.

I always try to get sun shots before 9 or after 3 as strong light usually overexposes any combination at noon. Keep in mind sun strength as well as shutter speed.

THis photo is only 90th/sec f16 but is taken at 8am

http://bigblueimages.com/wbmvpai003.jpg

Lots of sharp rays there.

Hi Mike,

Cool thing about digital is exif info. Now, like you, I haven't taken my D70 U/W yet. But exif on the 5050 shows shutter as 1/1000. My guess is the exif on Starbucks shot also shows 1/2000 on his. In fact I know it does because I checked the exif myself. Also, when I'm shooting and adjusting speed, there is a difference in the exposure so there's no doubt in my mind it is.

Listed strobe sync speed for the D70 is 1/500. I wouldn't be surprised that it's more than fast enough for what I like to do.

As for the time of day, both shots were taken either late morning or early after noon. I can't say for sure, but both are from dive boats that left in the morning and returned around 1:00 pm. The first one is from the Sea of Cortez and I know it had to be getting on toward mid-day as it's from a pinnacle we dove as a second dive and the top was at 100'. The second from Fiji was in about 30' of water. Don't let the angles fool you. As I progressed through the learning curve, I found getting low and shooting strait up into the sun vs an angle, worked better. The eel shot was at an angle, the soft coral was shooting out from a wall allowing me to get beneath it.

It's hard not to type out a long boring message on what I've tried over the last year or so to make this work. Comparing digital results to film is not apples to apples.

Anyway, enjoy your D70 I'll be interested in your feedback and especially experiences shooting sunballs/rays.

Rand

I have shot with the Nikonos for years, i know that i could set my shutter speed to 1000th of a sec with my strobes on and get synch. However, i was not actually getting 1000th/sec synch i was only getting 90th/sec synch as the camera could not synch higher than that and would over ride the manual setting and give only 90th anyway.

The D70 does this too in the Subal housing with both the Sea and Sea YS120 and Subtronic Alpha strobes I tested, defaulting to the max synch speed of 1/500th when you turn the flash on (when the shutter speed was above 1/500th before the flash was on).

You have to fool the camera to get higher synch speeds - either by the strobe not communicating with the camera (e.g. Herb's Canon/Inon setup), by blocking all but two strobe connectors or by turning off the strobe.

Alex