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Old Jan 10, 2007, 3:44 AM   #1
jmc
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I just got my new Canon Digital Rebel XTi today. As I usually do, I've been comparing photos from my new camera with the photos from my old camera, a nearly 3-year-old Nikon Coolpix 8700.

I'm using a Tamron 17-50 lens, and shooting in Full Auto mode. This is my first DSLR.

The Canon is coming off very much the poorer in this shootoff, and I don't understand why. All my closer pictures - the furthest was a subject about 4' away - appear to be just slightly out of focus. A couple of pictures suggest that the camera is focusing an inch or two in front of where I'm aiming the center point at.

I confirmed this by taking a picture using manual focus. The photo is noticibly sharper, but still not as sharp as the Nikon's photo. Tried using the closeup mode, that was sharper still, but still noticibly soft, and nowhere near as sharp as the Nikon's image.

The one slightly more distant picture - of my husband at his computer desk - showed why I got the DSLR. The Nikon's pic was full of noise & my hubby looked flushed , while the Canon's was great, with good skin color.

But why do the closeups with this camera/lens come out so soft?

Thanks for any advice!
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Old Jan 10, 2007, 6:02 AM   #2
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JMC.....
Were you hand holding the close up shots???I have had pictures come out with
front or back focusing when I hand hold and try to get in tight...Your DOF is so short
any body swaying or movement on your part or the subjects part will throw the
focus off...Try putting the camera on a tripod or something stable and do your shots...
This will tell you for sure if you have a camera problem or lens problem with focusing...
I read alot about the focus issues and some even send the cameras back for a calibration...I would bet most focus situations are not camera related...
:?
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Old Jan 10, 2007, 10:35 AM   #3
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Maybe you should post a sample picture or two, so we can help you better.

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Old Jan 10, 2007, 1:55 PM   #4
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I thought of that, and did some comparison macros on a tripod. Sharper, but not sharp enough, and WB problems. Same image with the Nikon was clearly superior.

Attached is an example, cropped. Left is the Canon Digital Rebel XTi, right is the Nikon Coolpix 8700. The MP3 player photographed is just slightly bigger than a sugar cube - about 1" on a side.

EXIF info:

Exposure time: 1/15
Shutter speed: 1/15.00
F-stop: 2.8
ISO speed: 400
Focal length: 50.0000
Flash: Not fired
Exposure mode: Auto
White balance: Auto
Orientation: Top-left
Aperture: 2.9709

Thanks for any help!

jmc
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Old Jan 10, 2007, 11:25 PM   #5
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Here's another example. This is a house number, taken from about 10-15 feet away in cloudy daylight. The first is with the UV filter, the second without, the third is the Nikon. I thought maybe the filter was the problem, but apparently not.

Nikon: 1/89.3, f/3.5, ISO 50
Canon: 1/160, f/5, ISO 100

These are both on Programmable AE, so these are the settings the cameras chose. The Nikon's a lot closer to the true color of the bricks.

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Old Jan 10, 2007, 11:27 PM   #6
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... and another one. This is from the same pic as above, the outer bit is the actual color of the concrete as captured by the Nikon, the inner is the same area of concrete, as captured by the Canon. Shade, on an overcast day.

Thanks to everybody for their help!
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Old Jan 10, 2007, 11:36 PM   #7
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What are your sharpness settings? The mp3 player pics look like one with a flash and one without?

Which focusing point is being used(all of them or just the center one)?
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Old Jan 11, 2007, 1:26 AM   #8
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Sharpness was just above middle; both photos of the mp3 player were taken *without* flash. Center weighted focus.

I managed to get a better pic of the mp3 player in natural light - it's white like it should be - but still softer than the Nikon.

I just got back from shooting some lenses at the store, and those came out with decent color (including my own). I took one with my lense using a gorillapod, and that actually came out decently sharp, tho still probably not as sharp as the Nikon.

I guess the question is, is it possible that the $400 Tamron lens is simply outperformed by the glass in the Coolpix 8700?

One last try... I've set the sharpness to max on the Canon. I was having dof issues with the mp3 in the old position, so I took some pics straight on. The Nikon wouldn't even focus, which is why I dont have a Nikon image from that setup.

Anyway. Canon at maximum sharpness, natural light. I lightened up the image to be roughly the same as the Nikon image.

Interestingly enough, this time the Canon has truer colors, the Nikon's a bit red. I have mixed feelings about the sharpness here... the text looks softer in the Canon image to me, but the fine graininess of this tiny thing (can't feel that pebbling) shows, while it doesn't really on the Nikon.

Based on this image, should I be satisfied with the Tamron lens? This is about as good as it gets, I think, and I had to turn the sharpness up all the way to get close to the Nikon's image.

Any advice appreciated!

jmc

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Old Jan 11, 2007, 10:58 AM   #9
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With the XTi and the kit lens all my photos were soft but I turned the sharpness off to check the lens, But if I add USM then they turn out great. I also used the center focus instead of the 9 points. If you installed the zoombrowserEX and downloaded the pics with it it will show you which autofocus points it used.
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Old Jan 11, 2007, 12:08 PM   #10
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On the first set of images that you posted (Posted: Wed Jan 10th, 2007 11:55 am), depth of field is clearly an issue with the F-Stop of F/2.8 You can see than the text goes as of focus as you go from left to right. This also brings out another point. From how I understand it, you don't get the same depth of field with the same F-stop when comparing DSLR and P&S. PS& always have wider depth of field. This is why it's more focus througout.

Another point is that P&S's are sharpened in-camera. This is why it's hard to compare DSLR images with P&S's directly. DSLR's are designed to keep more details, while P&S's are design to do more in-camera edge sharpening as they expect users to do less post processing. Honestly, this is the first thing most new DSLR users notice. I know I did when I got my first DSLR/SLR 9 months ago.

I agree though that white balance is off with the DSLR. This is probably common with DSLRs on a less-lit area. This is why "good" DSLR shooters shoot RAW (CRW for Canon, i think). Because that way WB is virtually a non-issue as the camera doesn't apply it, it's stored as meta-data.

The brick images clearly shows hard edge sharpening on the P&S. Usually, this detail is not noticeable on prints, but it is on-screen -- especially when cropped or viewed at 100%.

I don't see the specs of the last cube images, but it looks like the depth of field of that one is better. Overall, taking into account what a P&S does internally, and what's posted here, I think the Tamron lens is better than the P&S. But you do have to do post processing, as even in-camera sharpening of DSLRs are pretty conservative.

What I would suggest is the following to a new DSLR user:
1) Do not shoot on any auto or P mode. Use Aperture, Shutter or Manual. I would start with Aperture for non-moving objects, and shutter for moving objects. This is the reason why you spent so much money on your DSLR.

2) If you are new to photography, learn the golden triangle of ISO-aperture-shutter speed.

3) Shoot RAW. You will need to do more post processing, but you'll get the image you want. I started shooting RAW two months after I got my camera, and I wished I started shooting RAW sooner.




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