How to shoot through curved glass

[SeaHorse_Fanatic]

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]

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]

Originally Posted by sphelps

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.

[sphelps]

Originally Posted by Ginu

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]

Originally Posted by sphelps

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]

Originally Posted by MarkoD

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]

Originally Posted by sphelps

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]

Originally Posted by MarkoD

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

[scubadawg]

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/R...ns-Review.aspx

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

[Ginu]

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.