100% pixel crop on 350D

Hi there everyone,

This is my first post.

I've looked around the site to see if this has been asked before but couldn't find anything, so I hope this is not a stupid question.

When reviewing images on my 350D viewer, when i zoom into the image, how do i know when i am looking at the image at 100% pixel size?

Like I said, sorry if that's a stupid question or has been asked before.

Thanks

I think that the viewer size is generally in the specifications. Taking that size and an assumption that most images begin with a 72ppi displayed resolution, you can work back from there.

What I do is zoom as far in as possible and move around a bit, but only to check sharpness. Exposure is only able to be reasonably judged by the histogram. Please do not use the lcd review for exposure. I used to do that and since the display is overbrightened, what would look good was actually underexposed and looked horrible at home.

Hope that helps.

Thanks for your reply.

Like you said, I only want to check sharpness of the image at 100%, so if I understand what you are saying, I should zoom in to the max to check that?

That's what I do and it actually is pretty accurate.

Excellent...

Thanks for your help.

Camera LCD screen is very poor choice for checking sharpness IMHO..
I use it only to check general composition, highlights and histogram.
Everything else is checked on the computer screen.

The LCD can zoom in 10 or 12 x magnification if I remember correctly, I"m not sure if that's even close to 100% crop. I'm not sure if the resolution of the LCD is high enough to fully guage the sharpness as you can do when looking at 100% crop images on the computer monitor.

i asked a related question similar to this on another forum and from the answers i got back i think that ( i'm willing to be corrected though )

i dont think the playback actually zooms to 100%, in fact i think it only even displays a sub-res picture anyway. ( i.e. it reads the full file, downsamples it, then displays the lower res file )

I think this ties in with when your shooting RAW too. i was told that the RAW file also saves a preview JPEG thumbnail of the image into the file for the camera to read quickly during playback. again, a downsampled version of the full RAW file. this speeds up the playback without significantly affecting the RAW file as a whole ( a few hundred jpeg kb added to a 7mb file is nothing )


at least thats how i understand it.

Wow, I don't think it will zoom in any where near 100% will it?...I have never been able to really check the sharpness on the cameras screen....then again I shoot with the 20D...is there that much difference in the LCD ?

Welcome to the forums.

The camera LCDs are much more useful for checking framing and exposure rather than absolute sharpness - you can generally tell (in jpeg moreso than the raw thumbnail as you can zoom in much further on a jpeg file.. the raw thumbnail loses resolution real quick) if it's okay enough to keep for now and check it out properly on a computer later.

I agree with not using the LCD on the XT to judge sharpness. I was totally bummed on my first shoot with my XT when I previewed shots in the LCD. Some were clearly out of focus, but most just looked soft until I got them on my computer. Now I only use the LCD for checking things like exposure(histogram) and composition.

on the rebel's 480x350 screen (estimated using the knowledge that it is not 2x3 and it does have 115000 pixels), the rebel xt's 10x playback zoom is actually zooming in more than 100%. at 7x the playback should be about 100%, any any more than that is not going to help. if you have ever wondered why the photos look much blurrier at max zoom on the camera than at 100% when looking in your computer, that is why. key is, don't use max zoom to check for sharpness, it's pointless.

That's very interesting. I counted 15 steps in the zoom. Any idea which one would be 7x?

As others have said....the LCD is a very poor tool to judge just sharpness of a pic.