can we decrease resolution to increase image quality?

[vichio]

Hi everybody,
i have an unsolved question. Recently 50D review on dpreview show that 15Mbpx makes 50D's image quality worse than 40D which is 10Mbpx. Many people suggest that a 1.6x crop body of 35mm format should only got maximum around 12 Mbpx. However, 50D let us have the choice to choose which resolution we want ( around 15Mbpx, 7.1 Mbpx & 3.7Mbpx). So if i choose 7.1 Mbpx, could the image quality goes higher?
Pls help me. Thanks :)

[chauncey]

Can you provide a link to your source, I'm confused.

[John_B]

vichio,
My guess is its do to the size of the pixels, the larger the pixel the more light can be captured which effects quality.
Just changing the file size in your camera doesn't change this.
So my guess (as I don't own a 50D) is no, choosing 7.1 mp file size wont give you a better image quality.

[PhotosGuy]

Can you provide a link to your source, I'm confused. Me, too.

I'd like to know what the IQ "problem" is? I suspect that the IQ "problem" is that the OP is seeing more noise due to higher resolution.

[John_B]

PhotosGuy,
I am not sure if this is the exact one the op refers to but here they do compare and show photos with crops of the 50D and 40D at dpreview.com
and say:
As we've mentioned previously in this review, in terms of per pixel sharpness the 50D cannot keep up with its older sibling and shows only very marginally more detail (despite the fact that Canon told us the strength of the AA filter remains unchanged for the new model). In fact, the 50D's output and a 40D image scaled up to match are virtually indistinguishable (thanks to Picture Style the tone and color responses between these two cameras is as good as identical). <-- click to see (http://www.dpreview.com/reviews/canoneos50d/page21.asp)

[Picture North Carolina]

Vichio,

In answer to your question, (as I understand it), no. The canon 5D MK I image quality is still considered excellent, even in today's market. One of the the reason is because the pixel size on that camera's sensor is large. As a result, they are capable of capturing more light with less noise and with an increased ISO range.

The 50D has more pixels in a smaller space, meaning pixel density is higher meaning pixel size had to be smaller.

I do not know how canon achieves those stepped down file sizes you mention, but it looks like each step is roughly half. Perhaps they're using every 2nd, every 4th pixel - but I don't know. But whatever the algorithm is, the physical size of each pixel on the 50D is not being increased or decreased by changing a setting on the camera.

[HappySnapper90]

. However, 50D let us have the choice to choose which resolution we want ( around 15Mbpx, 7.1 Mbpx & 3.7Mbpx). So if i choose 7.1 Mbpx, could the image quality goes higher?
Pls help me. Thanks :)

In theory yes, as the DPR review shows Canon went too far the the 50D give the same quality as about a 40D shot enlarged to 15MP. So shooting one of the sRAW sizes should give better looking results.

And if you are shooting for snapshots and at most an 8x10 print, you can always shoot the 7MP sRAW to give you smaller file sizes that won't hog up your hard drive.

[Picture North Carolina]

Hmmm, interesting. Never occurred to me he may be asking about the various RAW and JPG quality settings. Vichio, if that's what you're referencing, then yes - shoot RAW. That will be the best quality you can get.

[vichio]

actually what i mean is: Does 7.1Mbpx (M size, JPEG or RAW) in 50D deliver better image quality than 15Mbpx (L size, JPEG or RAW) ?

[DStanic]

actually what i mean is: Does 7.1Mbpx (M size, JPEG or RAW) in 50D deliver better image quality than 15Mbpx (L size, JPEG or RAW) ?

I don't think it's possible for it to be better. Close? Probably.

If you wanted to shoot at 7.1mp why not just buy a 30D for $450 then? lol



This is the first time I've read the Dpreview review on the 50D. Gotta say my next camera will be a 40D, since I don't want to shoot at 16mp (and not have better IQ to go with it).

[vichio]

I sold my 30D before bought 50D 2 weeks ago ^^
with 50D i got AF microadjustment, faster & reliable AF, better LCD screen, better VF, vignetting control, auto ISO etc.
Why I wonder about 7.1Mbpx vs 15 Mbpx ?? It's simple, everyone want better image quality. Though my experience with 50D is very good, i can happy shoot until ISO 2000 without notice any noise issue :) ( not to mention my old 30D had very much banding at ISO 1600 ^^)

[sandpiper]

I sold my 30D before bought 50D 2 weeks ago ^^
with 50D i got AF microadjustment, faster & reliable AF, better LCD screen, better VF, vignetting control, auto ISO etc.
Why I wonder about 7.1Mbpx vs 15 Mbpx ?? It's simple, everyone want better image quality. Though my experience with 50D is very good, i can happy shoot until ISO 2000 without notice any noise issue :) ( not to mention my old 30D had very much banding at ISO 1600 ^^)

As you have the camera, why not simply take some shots at each setting and see what the difference is?

I suspect that you won't be able to tell (maybe you have tried it already and that is why you are asking us). In which case, why worry.

You say that your experience with the 50D is "very good", so presumably you were happy with the image quality, until you read a review telling you it isn't very good and now you don't like it :rolleyes:

It seems that a lot of people, who were previously very happy with the results from this camera, are now complaining that it isn't very good because one review has told them so.

If you find something you don't like about the images you produce then you need to look into it, but if you are happy with them then don't worry about a review. Is there something that disappoints you about the images when you look at them ?

[DStanic]

DSLRs (from all manufacturers) have come a long way. Canon and Nikon are head to head, with my general conclusion that a $1700 Nikon will be *slighly* better than a $1500 Canon- just as a $8000 Canon will be better than a $5000 Nikon. Even Pentax and Sony are not too far behind, much better than they were previously anyways.

The main thing about the 50D (over the 40D) was overall improvement in features to compete better with the D300. In the end, it's all about the glass anyways.

[vichio]

As you have the camera, why not simply take some shots at each setting and see what the difference is?

I suspect that you won't be able to tell (maybe you have tried it already and that is why you are asking us). In which case, why worry.

You say that your experience with the 50D is "very good", so presumably you were happy with the image quality, until you read a review telling you it isn't very good and now you don't like it :rolleyes:

It seems that a lot of people, who were previously very happy with the results from this camera, are now complaining that it isn't very good because one review has told them so.

If you find something you don't like about the images you produce then you need to look into it, but if you are happy with them then don't worry about a review. Is there something that disappoints you about the images when you look at them ?

Thanks, however, as i said :"everyone want better image quality". In that case, i NEVER SAID i DID disappointed in 50D image quality :D If there is a way to get better image quality from the camera, why not? ;) That why i'm concerning about this issue, hope someone can solve it for me. Thanks :D

[sandpiper]

Thanks, however, as i said :"everyone want better image quality". In that case, i NEVER SAID i DID disappointed in 50D image quality :D If there is a way to get better image quality from the camera, why not? ;) That why i'm concerning about this issue, hope someone can solve it for me. Thanks :D

Like I said, just shoot comparison shots with your camera, using both the 15mp and the 7.1 mp settings and see what the difference actually IS. If you can see an improvement using 7.1 mp then you have answered the question.

If you can't see any difference, then you have answered the question as well. :)

Either way, you will be able to judge for yourself, from the results in front of you. That should solve it for you.

[Sorarse]

If you are thinking of having some enlargement prints made, surely that will have a bearing on what setting you choose to shoot at. I would have thought that a 15mp image would allow you a bigger enlargement without losing quality.