Slowest Shutter Speed

I have been going through my photos and noticed that many seemed soft. (Leica Dluxl-4/Panasonic DMX3) I first I thought it was because of the lens. But then here and there I noticed a few that were really sharp. I finally realized that while I was shooting Av priority my camera set the shuttler speed to be 1/30. This was the case 80%-90% of the time. The other time it was faster.

I thought this strange as I figured that when forcing the flash to be on that the minimum shutter speed would be 1/60 all of the time. Not so seems that 1/30 is minimum and yet when there is enough ambient light it will be faster.

Interestingly if I shoot in fully auto mode I can set the minimum shutter speed - but it does not work when shooting in aperture mode.

So what this tells me that shooting in aperture mode is not really that useful.

What if you set the exposure compensation to -1? Then you will get 1/60th 80-90% of the time :-)

Cheers

James

What if you set the exposure compensation to -1? Then you will get 1/60th 80-90% of the time :-)

Good point, I did not think about trying that.

For many of my dives in Palau there was a descent current so even 1/60 might not have been fast enough to avoid some blur so I could try -2 but at that point it would seem just going to full manual would be better. So a side question - are folks often setting a shutter speed for the overall conditions and leaving it then adjusting the f-stop and flash according for a each shot. Seems like trying adjust all three/four (EV) could be trying.

Also check your metering method. "Spot" vs. "center-weighted" will usually result in shorter exposures, all other conditions being the same. (Assuming of course you have something in the foreground and the majority of the background will be darker, e.g. water.)

I got bit by this myself - left the camera in center-weighted after some topside shots and got soft pics with lots of 1/30th exposures - the strobe-lit part of the shot is crisp but with an aqua 'halo' effect around edges as the long exposure allowed ambient light to fuzz into what the strobe lit up. And you can't see this on your review shots without zooming in, nor does the histogram look bad. So I wasted a whole dive day that way....

Eventually I think we both oughta learn full manual. I'm just not there yet either. My current settings are (when I remember to get them right!): Aperture priority, starting about 5ish. Strobe on TTL. Spot metering (and if I want my main subject off-center I center it first for the half-press to lock focus and set the exposure, then re-frame before the full shutter depress) and rely on TTL to take down the strobe. EC default to -1.3 or so on entry, then bump it up or down a bit based on how the histogram looks after shots or if I make a major choice to alter aperture going for different DOF effects.

I agree with you that ability to set a minimum shutter speed (same as camera sets an automatic max shutter speed when forcing flash on) would be a nice feature in A-priority mode.

i prefer full manual shooting, adjusting the shutter speed to balance on the fly. however, if you wanted to shoot aperture priority, why not simply check your exposure once your under? get to depth, and check the cameras meter pointing in different directions. that should give you an idea of what your slowest and fastest shutter speeds will be on the dive. then adjust your aperture or iso to keep it above 1/30th.

also, i'd almost never balance ambient exposure when shooting with strobes, ambient should be compensated at about -1 or even -2 to get that nice dark blue water, filling in the foreground with your strobes. i haven't seen your photos, so i can't judge, but as per your response to james' post, the biggest mistake most people make when learning to shoot UW is letting the camera tell you what ambient exposure to use. the resulting photos are a light washed out cyan colour instead of the deep blue we see with our eyes. if you're shooting with flash, one can't first fully expose that subject with ambient light then add more light with strobes.

again, not assuming your photos are like that, just thought it's worth mentioning. cheers,

chris

No need for the 'cautious' tone...I take no offense at all, and rather sincerely appreciate your post and the way you are helping me think my way through the minefield Mucho gracias!

I have been going through my photos and noticed that many seemed soft. (Leica Dluxl-4/Panasonic DMX3) I first I thought it was because of the lens. But then here and there I noticed a few that were really sharp. I finally realized that while I was shooting Av priority my camera set the shuttler speed to be 1/30. This was the case 80%-90% of the time. The other time it was faster.

 

I thought this strange as I figured that when forcing the flash to be on that the minimum shutter speed would be 1/60 all of the time. Not so seems that 1/30 is minimum and yet when there is enough ambient light it will be faster.

 

Interestingly if I shoot in fully auto mode I can set the minimum shutter speed - but it does not work when shooting in aperture mode.

 

So what this tells me that shooting in aperture mode is not really that useful.

I don't know if this is applicable. I set my DSLR in M for manual and the exp. 1/125 to 1/160. I find a slight improvement in image sharpness. I use ISO 100 or 200. You can always bump the ISO a little as needed. If the histograms say the exposure is good, but there is a little undesired blur in the shot, bump the ISO to get a faster shutter speed.

Bob

I'm about to go on my first dive trip with a D90 next month and was thinking about this minimum shutter speed issue, as I shoot AV topside pretty much all the time. I also tend to use Auto-ISO; I'm not sure how this behaves on other cameras but on the D90 you can set the max ISO (I'm happy up to 1600) and you can also set the minimum shutter speed (which I have set to 1/60).

What do people think about using auto-ISO under water, and is this a good way of ensuring at least 1/60 while in AV? For me I'm hoping there'll be less to worry about if I do things like this: I just have to set my aperture, EC and strobe power while ISO and shutter speed are taken care of.

Cheers,

Tim

I'm about to go on my first dive trip with a D90 next month and was thinking about this minimum shutter speed issue, as I shoot AV topside pretty much all the time. I also tend to use Auto-ISO; I'm not sure how this behaves on other cameras but on the D90 you can set the max ISO (I'm happy up to 1600) and you can also set the minimum shutter speed (which I have set to 1/60).

 

What do people think about using auto-ISO under water, and is this a good way of ensuring at least 1/60 while in AV? For me I'm hoping there'll be less to worry about if I do things like this: I just have to set my aperture, EC and strobe power while ISO and shutter speed are taken care of.

 

Cheers,

Tim

From my personal experience, I try to tweak camera settings before I even splash. I want to adjust as little as possible while I'm down there. This is even more important when doing drift/current dives when you exhaust yourself by trying to stay in the same spot long enough to adjust shutter speed/iso/aperture to take a photo.

While others may disagree, I like to set out on dives with photos in mind (i.e. this is going to be a macro/wide-angle/etc dive).

When I am doing wideangle stuff, then I am in full manual mode. I usually set a Fstop=8-9 already before the dive starts and it usually stays there. Then I am continously metering the bluewater and setting the shutterspeed about a -1 stop. I usually start at ISO100 and if the shutterspeed goes below 1/60 I bump the ISO. If the fish is fast, then I want a faster shutterspeed.

For macro I am using the A-mode ( Aperature Priority) with a max shutterspeed of 1/60s and ISO100, most of the time.

I'm about to go on my first dive trip with a D90 next month and was thinking about this minimum shutter speed issue, as I shoot AV topside pretty much all the time. I also tend to use Auto-ISO; I'm not sure how this behaves on other cameras but on the D90 you can set the max ISO (I'm happy up to 1600) and you can also set the minimum shutter speed (which I have set to 1/60).

Tim,

I see you are about to head out for D90 shooting with the tokina 10-17 and Z240. I am recently back from my first trip with that setup. The shots included below were my first day with this setup so I am far from being an expert with it. I used D90 in manual: 1/125, F8, ISO 400, manual flash set at the click between f8 and f11 on two Z-240's.

The sand tigers were a bit brighter than I wanted and had to be toned down in post processing. Same with the hot spot on U-352. If I had it over, I would have used the f8 setting on the strobe or shot at f11.

This histogram did not show any overexposure during the dive but the results might have been better with slightly less flash output.

If you blow the shots up, the shark teeth are reasonably well detailed, which I thought was critical for the shots.

I think 1/60 would have generated a bit of blur.

All photos shot mid-day, relatively clear water, 110-120 ft.

Closeups of bottom dwellers with sandy bottom with this setup were definitely overexposed with that strobe setting, f16 would have been a better choice.

Hope that gives you some ideas for a place to start.

sand tiger

sand tiger at spar

next sand tiger

U-352

Thanks Dave,

Nice shots and thanks for the settings tips. Got my housing last week (a Hugyfot) but there's a problem with the dome port so I'm still waiting on that. I've been using manual mode a lot more recently so I guess I should use that to set my minimum shutter speed, now I'm getting used to the housing I'm a bit more confident I can control more things at once. Only have one z240 (and no strobe cable yet) so lighting at 10mm is going to be interesting..

Cheers,

Tim