PDA

View Full Version : How to shoot through curved glass


Ginu
02-21-2012, 08:39 PM
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

SeaHorse_Fanatic
02-21-2012, 10:27 PM
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.

sphelps
02-21-2012, 10:32 PM
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.

Ginu
02-21-2012, 10:32 PM
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.

Ginu
02-21-2012, 10:34 PM
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.


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.

Delphinus
02-21-2012, 10:37 PM
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."

MarkoD
02-21-2012, 10:58 PM
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.

sphelps
02-22-2012, 01:47 AM
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.

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.

MarkoD
02-22-2012, 02:29 AM
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

sphelps
02-22-2012, 02:47 AM
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.

MarkoD
02-22-2012, 05:56 AM
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.


anything higher than 70 cm wont really distort.

i've shot 70-200 with extension tubes at f8 (on a tripod) with perfect sharpness.

what i would recommend for the OP is to put the camera on a tripod, turn on the live view mode and zoom in to 100% on the screen. Then manually adjust the focus

Ginu
02-22-2012, 07:02 AM
Why would it be hard to get anything sharp? I use a 70-200 f2.8 on my tank all the time


Well unfortunately, I don't have any primes to use :( my list of lens is above.
I am eventually going to get some primes but for now that will wait.

I've taken some pics from about 7-8 feet with the 70-300 VR and to be honest pics are quite decent, can actually see the scratches on the inside of the tank :(

I'm pretty sad though, I started this tank about 3 weeks ago (bought from a fellow reefer) and today I noticed the yellow tang hide and sit in the corner panting... needless to say i took him out immediately and quarantined him in a 2 gallon tank i had sitting around. I took 1g from the main tank and another 1g from my mixing bucket, however hes now on his side and don't believe he will make it through the night :(... he looks fairly paralyzed now, just breathing...

Any chances anyone might know what caused his downfall? he was fine and eating yesterday, however hes always had a whitish rash on his side as in the pics further below. I will post in the disease forums and perhaps someone might know what this is. I am now afraid of the other fish and shrimp picking this thing up... whatever it is although it doesn't look like itch...

http://oi43.tinypic.com/349cti0.jpg

http://oi43.tinypic.com/29ct8o3.jpg

http://oi41.tinypic.com/28vg95k.jpg

http://oi44.tinypic.com/2ltoz7b.jpg

http://oi40.tinypic.com/95wvsz.jpg

scubadawg
02-22-2012, 08:43 AM
You can buy a Canon 500D closeup filter in 77mm, I have one, never really used it too much, I have the Nikon 60mm micro, 105mm micro and the 105mm VR micro.

It's a great closeup filter to use on your telephoto, to give you Macro lens with a fairly long shooting distance, I tried it on my 70-200 VR.

http://www.the-digital-picture.com/Reviews/Canon-500D-Close-up-Lens-Review.aspx

http://xoomer.virgilio.it/ripolini/whatsnew_2.html

Ginu
02-22-2012, 09:06 AM
I'll have to try that. Thanks for the suggestion.

On a side note, the foxface died :( and not sure what exactly got him. Now I'm afraid to add anything to the tank and contemplating if I should pull out my old 10gallon fw tank and turn it into a quarantine tank for the two clowns and cleaner wrasse.

Sad time though.

scubadawg
02-22-2012, 09:14 AM
Sorry to hear that, I'm a first time reefer, getting my tank setup next month.

MarkoD
02-22-2012, 01:23 PM
Um, 34 gallon tank is way too small for a yellow tang and foxface. They're probably dying from stress.

And putting your yellow tang into a 2 gallon container will do thing but kill it.

you shouldn't get large species fish for such a small tank

Ginu
02-22-2012, 03:04 PM
Yep I am aware 34g is small for a tang, however it wasn't planned(fish was given to me as it was going to die in tank with two 10" + tangs) besides the fish was only 1.5-2" at max, so for the time being I think it was ok.

And I had no choice in regards to putting him into a 2g... It was the only thing I could set up as a qt in a very short time.

By the time I moved him there, the fish was on its side, so the last thing he was going to do was swim around. I just need to know what disease that was in order to make sure it doesn't spread to the dt.