sensor size differences among eos dslr

[erwin_casicas]

I am wondering what are the implications on the quality of the captured image

when using a canon eos 400D/xti against that which is captured using a canon

5D and/or 1D. The canon brochures describes the 5D and 1D as having a sensor

whose size is that of a 35mm film. Does the 400D/Xti possess the same sensor

qualities?

[mawz]

The XTi's sensor is significantly smaller than the 5D/1Ds, this is reflected by the 1.6x crop factor. The 1D also has a smaller sensor than the 5D or 1Ds, but it is larger than the XTi's at 1.3x crop.

 

The size of the sensor mostly affects high ISO noise and wide angles. The advantages of a bigger sensor really come down to being able to have more pixels without running into serious high ISO noise issues. You also get bigger viewfinders and more wide angle options with a 35mm-sized sensor.

[bluphoto]

I've also heard that you get shallower depth of field with the larger frame sensors, although perhaps that's just a side effect of having to use a longer lens to get the same image in frame.

 

Personally I can't work out why a larger sensor would give less DOF as you'd think that that would depend solely on the lens / aperture etc.

[davebell]

Guy,

 

I agree. The only reason for less DOF with a full frame sensor must be the fact that you have to use a longer lens (from the same position) or move closer to the subject to get the same FOV compared to a crop sensor, both of which will give a shallower DOF. I think we're right, and if not let the guru's correct us with a nice explanation.

 

Dave

[digitmstr]

>>...the implications on the quality of the captured image...<<

 

Image quality has to do with many factors, including the the size of the sensor's pixels. Generally speaking, the smaller the pixels for any given size the more noise is produced forcing the manufacturer to use harder anti-noise algorhythms.

 

The 5D's pixels are larger than the 400Ds thus you can expect less noise on the 5D. I believe practical tests will confirm as much.

 

The 1DMKII has the same pixel size as the 5D but, the 5D has a more of them since it's a FF sensor. That would give an edge to the 5D if one were to frame a subject equally with both cameras.

 

The DOF is greater on smaller sensors because the FOV is such that you need to step back (increasing the distance) from your subject. P&S cameras for example, havea huge DOF compared to a DSRL. Likewise there was/is a noticeable difference between my 10D and 5D, using the same lenses.

[richard_hopkins]

Depth of field is dependent on two factors.

 

One is the f/number, the other is the image size. Smaller sensors inherently give more depth of field (eg camera phone) than a full-frame SLR, for example.

 

The difference between depth of field on a 1.5 or 1.6x D-SLR over a full frame 35mm camera is about 1.25 stops.

 

Richard,