Digital zoom OR cropping?? (1 Viewer)

Digital zoom OR cropping to eliminate vignetting??

Hi, I've recently gotten a Sony Ericsson mobile phone, mainly for birding purposes, it claims to have a 3.2 Megapixel camera and I have been holding it up to my scope (Nikon Spotting 20x) with reasonable success for digiscoping.

Obviously, there is considerable vignetting going on. The camera has a 16x digital zoom (absolutely rubbish as you near its limit), but no optical zoom. My question is; is it better to zoom in a bit to get a clear picture with no vignetting, or to crop the picture later on, to get the best results?

(BTW The reason I'm asking without testing it out is because I don't think I've got any programs to crop with)

Cheers, Dan

I always avoid digital zoom. The reasoning is that a longer lens magnifies any shake/ vibration. Using the computer to crop a photo is just like digital zoom - but no shake/ vibration.

Dan, I'd have thought the ideal way to determine this and other "best" camera settings would be by doing some tests. As an example, in this post Jay Turberville discusses the results of some tests he did to try to determine what level of in-camera sharpening to use with his digiscoping setup :
http://www.birdforum.net/showpost.php?p=202383&postcount=14
Presumably the vignetting has some impact on the camera exposure setting causing the camera to tend to overexpose. You'll need to find a way round this if you wish to avoid using the zoom.
Must say, from the image processing viewpoint it does seem pretty unlikely that the in-camera upsampling part of digital zoom is going to be a welcome. Then again it should be possible to postulate a situation where it could be. Perhaps where severe jpeg compression made nasty artifacts on a sharp picture with lots of noise, but less mess on a softer upscaled version of a detail from it.

dantheman said:

(BTW The reason I'm asking without testing it out is because I don't think I've got any programs to crop with)

Click to expand...

In that case I'd recommend downloading FastStone. It's a great image viewer and has a decent crop function. And it's free.

Cheers. Wasn't sure as this was the best place to post this, as it is a pretty basic question. And I'm using the setup for record shots rather than 'digital photography' although should be able to get reasonable results. I suspected digital zoom was a 'no' even if you can't see a discernible effect by eye.

I've downloaded the faststone program, will have a play, and I will also have a play to see how exposure turns out with/without vignetting. Would I be right in suspecting the camera only gets its exposure setting from the centre part of the screen rather than the whole?? I can set metering to normal or spot, and white balance to various lighting conditions, but no more.

The "spot metering" setting is designed so that the exposure setting is set such that the central spot of the picture will come out mid greyish in brightness. So that won't be affected by vignetting round the outside. (Might still overexpose a bit if the spot is on a matt black blackbird though). "Normal" could mean a simple "average" exposure which would lump vignetting and all into the area which determines setting, so that could overexpose. "Normal" could also conceivably mean some clever zone system which is difficult to understand but tends to give pretty good results when just left to do its business