Easy as Shooting Fish in a Barrel?

[FrankMi]

Perhaps, but there are a few things I need to learn first.

Until now, almost all of my photography has been using available light. Even my on-camera flash feels like it’s a second-class citizen. That has to change.

I wanted to take some shots of fish in an aquarium for my son, which has gotten me started using artificial light. There is a light over the tank which will give good exposure for the background on a tripod at ISO 800, 1/3 sec @ f16, focal length of 12mm.

The fish won’t hold still! No problem, the camera has a built in flash. Not having played with the flash before, I shot in Auto. Not good. The Nikon D3100 camera went to 1/60 sec @ f2.8 and varied the ISO from 140 to 640. The exposures were OK but the DoF went to pot and the flash didn’t freeze the fish motion as I had hoped.

Time to bring out the little ‘big gun’. When I bought the camera I also got a Nikon SB400 flash in case I ran into a situation where the on-camera flash needed more umph! In Auto, the camera went to 1/60 sec at f4.0 with the ISO around 500 and although this was marginally better, frankly, it sucked!

I am shooting at about a 45° angle to the tank to avoid the reflection of the flash from the glass on the tank. Here is one of the better shots.



I think I need to shoot in manual mode but I’m not sure how to configure the settings. The fish are about 18-36 inches away from the focal plane. I think I need to maximize the DoF as I am having trouble focusing on moving fish behind the glass.

If there isn’t a simple starting technique, can someone point me to a tutorial that addresses this type of issue? Thanks in advance!

[jiro]

If you shoot in manual mode, use the fastest sync shutter speed for flash that your camera can offer. Typical is 1/250 second. Then start at any aperture setting, say f/5.6. If you can override the power output of your SB400 in-camera start at the lowest, say 1/16th power and do a test shot. Overexposed?... stop down your aperture at f/8 then fire another test shot. Better? if not, continue to narrow down your aperture until the flash exposure looks natural. If you want to include the ambient atmosphere of the tank, slow down your shutter speed to 1/125 for a start. Remember the code for flash photography: SAAF - Shutter speed controls the Ambient light, Aperture controls the Flash exposure. Do a lot of trial shots and in no time you will master it. Good luck, Frank. Your shot looks good to me. Try a different POV to make it more interesting.

[Sam Smith]

Willie, Good point never heard had before-SAAF good way to remember it. Got a thumbs up.

[FrankMi]

Hi Willie, thanks for responding.

To change the point of view, I should be able to shoot straight on and use the SB400 flash at a 45° angle (rather than set the camera at a 45° angle) to keep the reflection out of the lens, however, wouldn’t the side lit shadows would be much more apparent? I could also put the camera right up to the glass but that would really limit the viewing angle and I would need a way to keep the flash back at least 2’ without getting the camera’s shadow on the subject.

It looks like the DF3100 has a maximum 1/200 sync speed and the SB400 will need f16 at 2'-2'4" distance. I don't see a way to use the SB400 at anything but full power but I thought the purpose of the Nikon i-TTL capability was that it dynamically controlled the power of the compatible flash units like the SB400 so you didn’t need to set the power manually?

At 1/200 sec, the exposure time would be so short that the ambient light would have little to no effect on the exposure so it will be a flash lighting only with its light dropping off with distance.
The D3100 manual indicates that the manual mode flash options are Fill, Red Eye, Slow, and Rear Curtain. I’m guessing I need to use Rear Curtain?

One last thought. When you say that ‘Shutter speed controls the Ambient light, Aperture controls the Flash exposure’, couldn’t I leave the shutter speed at 1/3 sec and the aperture at f16 (to get the background exposure), and set the flash distance to 2’ to 2’4” to match the f16 needed? Or would that overexpose or perhaps not ‘freeze’ the motion the fish?

I’ll try all these settings when I can get back or to shoot again. Thanks for the feedback and tips. By the way, I like your new avatar!

[Dave Humphries]

Hi Frank,

I have done some of my sister's aquarium, using the available fluorescent light and working much closer, but I don't have the necessary HDD connected to PC with pictures on tonight.

I'll be back (tomorrow) ....

[jiro]

Frank, I think your SB400 can only be used in i-TTL mode so you can't be as creative as you can with your flash photography. I am not so sure if using a flash sync cord will work off-camera with the SB-400. I am using an SC-17 flash cord with my obsolete and manual mode only SB-24 on my NikonD70 so I can control the flash output and the zoom coverage. The SAAF method won't work much for you. What you can achieve though is a very good fill-in light from your flash due to the i-TTL mode.

If you change the angle of your camera relative to the aquarium, you need to see where the "family of lines" would fall. Otherwise, what you'll see are mostly reflections from the surface of the aquarium glass itself. Reflections go in straight lines so you can visualize it yourself.
The only real solution here is to experiment and learn. If you can use an external light like Dave said that can help you a lot. If you use a slow shutter speed I don't think you can capture the fish right due to blur. Good luck.

[FrankMi]

Hi Dave,

here is one of the first shots I took without the flash - just the ambient light from above the tank.



In comparing these two images and discovering the fact that the default flash setting was Fill, I am beginning to wonder if the real problem was that Auto with flash dropped the aperture down to f2.8 from f16?

I wonder if I just went to manual mode at f16 that perhaps the image would have been much sharper?

I've been looking solely at the sharpness of the fish and thinking that the flash wasn't freezing their motion but maybe it was and the softness was due to the aperture setting instead?

I'll need to get back over there and try some of Willie's suggestions and see what happens.

[FrankMi]

Hi Willie,

I have a couple of CFL floods I can mount with spring clips at a 45° angle to either side. I could then shoot straight on and not be concerned about syncing the flash to the ambient light?

I just checked my flash cord and it has the same number and location of connections as the camera shoe so the iTTL may work. I'll need to test it to see.

It looks like I'll need to play with the shutter speed but if I raise it too much I'll loose most of the ambient light. That might be the price I'll have to pay. Seeing how much you've progressed by experimenting I'm encouraged that with a nudge in the right direction I can get it right! Thanks again!

[jiro]

The reason why flash photography looks so crisp and so sharp is because the "strobe effect" of the short duration burst of light can really freeze the action of your subject even at a mere 1/60 more so at a good speed of 1/125 and 1/250 second. The only way you can realize this is to do it yourself. Once you do it, all your questions and doubt will be replaced by conclusions and "ah.. so that's how it works." What I noticed is that you really learn more by making mistakes in photography. So what if my first two shots are horrible? Now, I've learned not to take two shots that way. If you really want to learn flash photography faster and better I would suggest you buy the cheapest obsolete model of Nikon flash that you can buy. I think my old SB-24 flash (a gift from a fellow photographer at DGrin) sells for less than $40 at ebay right now.

Shooting in full camera manual mode and using the flash in full manual mode will teach you a lot than reading books, Frank. Peg the shutter speed at one setting then play around the aperture, you'll immediately see how aperture affects the flash exposure on your subject given that you are NOT changing the flash to subject distance. Then use the best flash exposure you got from the aperture setting and keep it. Now, change the shutter speed and watch how your background comes alive! You can't achieve this with natural light. That is the wonder of flash photography. Suddenly, your camera has two personalities! Hahaha. One for ambient and one for flash. I would highly suggest you start with still subjects first. Good luck and you better post your experiments so others can learn from you, too.

[FrankMi]

Hi Willie,

I agree completely about the learning. My son is so busy that it is difficult to get time at his place without interfering with his responsibilities so I try to make my visits brief and I can't check the results until I get home. It may take a while to run the gambit so to speak so I try to be as effectively prepared as I can in advance. I'll post the results as I can get them. Thanks again.

[Donald]

Remember the code for flash photography: SAAF - Shutter speed controls the Ambient light, Aperture controls the Flash exposure.

I would totally endorse what Willie says here (because I'm still trying to get it cemented into my tiny mind)

Syl Arena in the 'Speedliter's Handbook' tells us to think 'Safe' - SAAF: 'Shutter Ambient, Aperture Flash'. And to repeat it 1000 times.

[Colin Southern]

Syl Arena in the 'Speedliter's Handbook' tells us to think 'Safe' - SAAF: 'Shutter Ambient, Aperture Flash'. And to repeat it 1000 times.

Unfortunately, it's a bit misleading because the aperture also controls the ambient light energy, and above x-sync (ie when using HSS), the shutter also affects the flash light energy (since in HSS it's effectively a constant light source). In all honesty, in most cases I want to control the shutterspeed and the aperture -- at which point the flash output controls the flash!