Full frame sensor

[dds]

What are the advantages of a full frame sensor over the sensors currently employed in the 300D/10D?

Thanks

DDS

[Guillermo Freige]

Mostly, better wideangles (because the lack of crop factor) and more resolution. The larger sensor also means a larger and brighter viewfinder too.

[BrettD]

AFAIK there are 3 main advantages to full frame (35mm film size) sensors in DSLR's:

1. The larger sensor (more than 2x the area) collects more light, so a any given resolution there will be less digital noise (film grain equivilent), if all else is equal.

2. It enables a wider field of view with any given lense. IE a 17 mm lense behaves like a 28mm one on a 10D / 300D. This is good for landscapes.

3. The larger area also allows a larger viewfinder to make framing and manual focusing a little easier.

Anyone got any other reasons?

Brett D

[ron chappel]

There is slightly less depth of field with full frame.

Not much though-compared to the the jump from small digital sensors to full frame or full frame to 4x5"

[Belmondo]

There is slightly less depth of field with full frame.

Not much though-compared to the the jump from small digital sensors to full frame or full frame to 4x5"
Is this really true? I always though DOF was a function of the optics. In other words, the DOF of, say, a 50mm f1.4 will be the same with identical settings on a 1Ds, 1D, or 10D. Only the FOV will be different.

I.M. Confused (Thos)

[slin100]

People are generally interested in comparing DOF when the FOV is the same, not when the optics are the same. When the FOV is the same, the DOF of the 10D is going to be 1.6x greater than that of a full frame sensor. It's no accident that the factor happens to be the same as the misnamed 1.6x "focal-length multiplier".

DOF is highly dependent on the size of the final output image because it's the overall magnification of the circle of confusion (CoC) that determines DOF.

This article (http://www.photo.net/learn/optics/dofdigital/index.html) is the best in explaining DOF on digicams in relatively simple terms.

As the article says, the only time you are going to get identical depth of field when using the same optics is if you crop the full-frame sensor down to the same size as the 10D. If you don't crop the full-frame sensor, then the DOF of the 10D will be 1.6X less if you magnify both images to the same size. The reason is that the 10D image needs to be magnified more so the CoC is magnified more.

[Belmondo]

Okay. That makes sense, I guess that such statements about DOF really have to contain a few qualifiers in them including a references to equivalent FOVs.

I was interpreting Ron's statement as saying, "There is slightly less depth of field with full frame---where everything else is the same." That would have included optics, but I guess I was reading more into it than I should have.

Thanks for the link. I will read it. I hate confusion even though it's my normal state.

[MediaMagic]

I've read a few articles referencing a vignetting problem with the full frame digital sensor of the 1Ds. From what I can remember, this is caused by the sensors inability to capture light falling at an angle at the edge of the sensor.

Can someone who uses a 1Ds regularly elaborate on this? is it a real issue that you have to deal with on a regular basis or is it just something that occurs under specific conditions? How do you get around it?

[Tom W]

I've read a few articles referencing a vignetting problem with the full frame digital sensor of the 1Ds. From what I can remember, this is caused by the sensors inability to capture light falling at an angle at the edge of the sensor.

Can someone who uses a 1Ds regularly elaborate on this? is it a real issue that you have to deal with on a regular basis or is it just something that occurs under specific conditions? How do you get around it?

The little that I've read on the issue is that it is more prominent on wide-angle lenses, since there is apparently a steeper angle that the light hits the sensor with. I read one test (in PopPhoto magazine) where the "digital" lenses had an advantage over some consumer lenses due to somewhat different physical characteristics that kept the angle closer to 90 Degrees and thus minimized light falloff at the edges. The same article gave Canon's 17-40 good marks in that regard, indicating that Canon considered this issue when they designed the lens.

I have to note that a couple of the "digital" lenses in the test wouldn't be useful with a full frame sensor, since they had the "APS" sized sensor in mind when they were designed.

[PacAce]

I'm still not sure how a larger sensor means a brighter viewfinder. I agree that the viewfinder area will be larger to accomodate the extra area but how does this translate into a brighter viewfinder. If you compare the same little area on a 10D viewfinder and a 1Ds viewfinder, I'm sure you'll find that they're both of equal brightness, assuming that a lens with equal max aperture is being used.

I also don't see how a larger sensor allows the collection of more light and hence less noise. I thought that was a function of the size of the individual sensor units, unless of course, you are implying that a larger sensor equates to the use of larger sensor units.

[Tom W]

I'm still not sure how a larger sensor means a brighter viewfinder. I agree that the viewfinder area will be larger to accomodate the extra area but how does this translate into a brighter viewfinder. If you compare the same little area on a 10D viewfinder and a 1Ds viewfinder, I'm sure you'll find that they're both of equal brightness, assuming that a lens with equal max aperture is being used.

I just compared the viewfinder of my 10D with that of my Elan II. Both were approximately the same brightness, but the Elan had a considerably larger image in the viewfinder, presumably due to its being sized to the sensor medium (in this case, 35 mm film). I did adjust zooms on both to give a similar image. I think its the larger image that gives the impression that it is brighter.

I will note that the Digital Rebel uses a pentamirror rather than pentaprism and thus might well have a darker viewfinder. I don't know - this is a maybe for me.

I also don't see how a larger sensor allows the collection of more light and hence less noise. I thought that was a function of the size of the individual sensor units, unless of course, you are implying that a larger sensor equates to the use of larger sensor units.

There's some missing information in earlier posts - a larger sensor of the same quantity of pixels should be capable of lower noise. For example, I think its safe to say that the 1D Mk II has a considerably cleaner picture than the Pro-1, even though both are 8 megapixel cameras. I would think that pixel density (and by extension, individual pixel size) rather than sensor size would be the greatest contributor to noise.

Somebody had an excellent post here a week or two ago describing the pixel size - vs - light wavelength and how that relationshop contributes to image noise. Suffice to say that as the pixel gets closer to the actual wavelength of the light wave that it is designed to sense, its actuation becomes less reliable.

Now, pixel quantity, if density is kept the same, would obviously be greater with a larger sensor. That should lead to better enlargements and greater opportunity to crop images and maintain quality.