Need help shooting SLR under blue lights

[CRW Reef]

so..... Can anyone help me with the settings on a Rebel XTI SLR? I have set the white balance using white paper under blue, set the ISO to 100 and the f-stop to 1/4. However every other few shots the camera will not focus and or if it is in focus, it will not take the picture.

Any thoughts from the pros?

 

[jahmic]

I have not taken out the dslr for the reef as my computer has been down for some time...but when shooting my FW tanks i found auto-focus to be fairly useless for close detailed shots. You would be better served getting accustomed to manual focus.

If you are trying to get shots of active fish...thats another story. But, in those cases you can shoot at around f8 to close down the aperture and use a remote flash (if you have one) to get a sharp image. That way if your subject is slightly out of focus the depth of field makes up for it and you still get a decent image. To he honest though...I still shy away from autofocus and just turn the focusing ring as I follow the fish. It takes some practice, but I do hate when the autofocus delays and you miss your shot.

In short...manual focus.

 

[CRW Reef]

Ok that makes sense, I thought I was manual focusing but I think you are right it is prob on AF. I am a complete novice btw and I'm using a borrowed camera

 

[jahmic]

My film slr is a canon, but the digital is a nikon. If your canon is like my nikon, there may be 2 switches for the af. One on the body and one on the lens itself. Check to make sure you aren't missing one and it should solve the problem.

 

[CRW Reef]

Yep that prob is it I knew the one the lense was on auto but didn't check on the body. Thank Khalis!!!!! Otherwise do the rest of my settings seem right to you and or anyone else reading this?

 

[jahmic]

No problem! Seems like you have the right approach. Is that 1/4 your shutter speed? If so, are you using a tripod? Also...if 1/4 is your speed (which is on the slow side) what fstop are you shooting at?

The kit lens for that camera should go as wide as f5.6...a lower number is wider open. I'm assuming that you have that set as wide as you can go due to the shutter speed and ISO setting you are using. If you don't have a tripod, bump up the ISO to 200 or 320 (if it lets you) so that you can get a faster shutter speed. Even with a tripod and the pumps off I'd still want a faster shutter than 1/4 to get a sharp image. If you can get close to 1/30 you should be golden...if you have a tripod or very steady hands.

The only issue with increasing the iso is that you will end up with grainier images...especially with that low blue light. Every camera is different though and I've seen my camera shoot more crisp images at iso 800 than 400. It will take some playing around to find what works, but my next step would be to start increasing the ISO and pairing it with a faster shutter to see if your images sharpen up.