Changed cameras; and I'm very perplexed

ljbad4life · Feb 10, 2009

Well I changed cameras from a Panasonic DMC-FX07 to a Sigma DP-1. The File sizes for the panasonic range from 2mb to 4mb roughly double what the Sigma produces. Even-though the Sigma has 14 megapixel and the panasonic has only 7.

The photo dimensions are larger for the panasonic (usually 3072x2304) than the Sigma (2640x1760). Of course the photos taken with the sigma are far superior (and can be enlarged much more before becoming distorted), but it just perplexes me to no end. How can a larger picture be of poorer quality when it was taken at those dimensions? Does the difference in saving a photo in raw or jpeg account for any size difference? sorry for the long first post, but any help is appreciated

tsaraleksi · Feb 10, 2009

It's not larger-- I think you've got the Sigma's res set down.

AlexColeman · Feb 10, 2009

Did you check the Dp1's settings?

ljbad4life · Feb 10, 2009

i've checked the settings, the dp-1 is set to as high image quality as possible and to save pics in raw format.

Edit* Well the only other factor I can think of is the editing of the photos after the fact. I use Aperture and Lightroom. The photo's I take with the panasonic i typically need to do far amount of editing while the Dp1 photo's are usually spot on and dont need that much editing.

tsaraleksi · Feb 13, 2009

But something is wrong here-- the dimensions you list for the Sigma are a 4.1 megapixel camera. There is something that is going awry in your workflow or inside the camera.

Katier · Feb 13, 2009

In my Pentax I can set the JPG file size to smaller than the sensor size. In my case I have 10/6 and 2mb as options. I wonder if :-

1) he's got the file size turned down and
2) he's not got the quality set to best quality.

ksmattfish · Feb 13, 2009

This is a great example why the term "megapixel" is almost completely useless, except as a way for salespeople to confuse buyers.

Megapixels tell you how many photo receptors a camera has, but all photo receptors are not equal, nor are they always used the same way. Many digital cameras use a sensor with all the photoreceptors on a single layer with a filter on top called a Bayer filter. The Bayer filter uses a pattern where out of every 4 photo receptors 1 is red, 1 is blue, and 2 are green to create color. The sensor in the Sigma DP1 is a Foveon sensor rather than a Bayer filter sensor. A Foveon sensor uses 3 layers of photoreceptors stacked on top of one another. In between there are colored filters; this is how color film works. This means that for every 3 photoreceptors there is only 1 pixel of resolution. So while there are 14mp of photoreceptors, there is only 1/3rd of that in actual resolution.

But resolution isn't everything. There are advantages to the Foveon sensor over the Bayer Pattern sensors, and vice versa.

foveon - Google Search

bayer pattern - Google Search