How to shoot through curved glass
 

Hey guys, I have a simple question in regards to how to shoot through curved glass...

I have a euro aqua 34g tank which has the front of the tank curved and have a really tough time getting anything in focus from the front...
For camera equipment I have the following:
Nikon D90 - gripped
Tripod/monopod
18-200 AFS
70-300 VR
50mm 1.8 AF
28-70 AF
SB 600

I'd like to add that I'm not a beginner in photography, been shooting for years, however I hit a wall with this curved glass...

Any tips on how to shoot in order to help with the focus? I am eventually going to get a macro lens f2.8 60mm VR or f2.8 105mm VR however that's down the road as I don't have a single macro lens.

Thanks in advance

I don't think there is an easy fix for this.

When I was doing my post-graduate work at UBC, we developed underwater camera technology for fish farms but we had to use a SuperVHS (30 frames per second), custom computer program and a lot of work on each image using a grid overlay to flatten out an image since the camera housing lens was bowed. If the image looks strange to your naked eye through curved glass, the camera will probably not be able to rectify that, as far as I know.

Build a camera box and take pics through the top.

You could also try a larger macro lens and taking pictures from further away. Not sure but I think the curved glass effect is worse the closer the lens is to the actual glass, if stepping back helps then a larger macro is the answer.

Well I figured its either something I cant figure out, or I'm doing something wrong.

The curved glass does project the image a little distorted or perhaps magnified but by any mean it does not look out of focus, however with the DSLR it doesn't matter if I let the camera to do the metering or i do it fully manual because its always out of focus...

Oh and ofcourse I try taking the photos with the pumps off... only works on the sides tho :( ah well

If anyone else has suggestions, please pot them up, I'm sure it will help a few people.

Yes you are correct on this, if i use the 70-300 and shoot from distance, the shot is way better than a macro shot up close. I will try this with the camera on a tripod and from distance as the shutter is quite slow for handheld.

You pretty much have to shoot as perpendicular to the glass as possible in front of your subject. I've never really understood the popularity of curved glass aquariums for this reason - eventually the novelty wears off and you realize you can't get a undistorted photo of your inhabitants. Also consider that these tanks are more prone to failure than your standard square tanks.

What's even worse are cylindrical tanks - nothing like the fun-house mirror effect with whatever you're trying to photograph. A prime example of (IMO) "just because you can, doesn't mean you should." I remember visiting a public aquarium a couple years back that had some (otherwise neat) clownfish/anemone displays but they were completely unphotographable because they were in tight cylindrical display tanks. :(

Maybe there is some kind of post-processing algorithm you can apply but I would think it would be heavily dependent on the camera position and angle which isn't going to be readily available to work with (beyond guessing), but as far as technique goes, I think you are pretty much limited to "try to avoid shooting at any kind of angle."

You can't compare what your eye sees to what a camera sensor sees.

Glass refracts light and the elements in the lens are precisely designed to give the best possible performance. But when you put another piece of glass in front of the lens at an angle that's refracting light it messes everything up.

Even when shooting hockey games, It's impossible for me to get a clear shot through glass if I'm not 100% perpendicular to the glass.

Just keep in mind a lens like a 70-300 will have a hard time getting a sharp pic in the best of circumstances. A prime lens is the way to go.

Why would it be hard to get anything sharp? I use a 70-200 f2.8 on my tank all the time

Same reason why macro lenses are prime. With a fixed focal length a prime lens can be designed to better reduce distortion and typically have better optical quality. For the most part the wider the zoom the more distortion you get resulting in a softer image. Not always an issue but trying to use a zoom lens in a macro type environment doesn't always work well, combine that with curved glass and you're really in trouble. Just something to keep in mind if you're trying to reduce one issue you may be introducing another one.

Now with that said one can't compare the 70-300 with the 70-200 you have, those are much different when it comes to optical quality and design, hence the price difference.