DigiRebel Kit Lens

DavidTO · January 6, 2005

Well, we all know the kit lens isn't a great lens, but I got a dramatic example of just how bad when my work bud got the 24-70 2.8L. He's no Fred Miranda, but then again Fred wouldn't bother testing the kit lens.

So here's a not completely scientific comparison of the kit and the 24-70.

All I can say is wow, and from now on I'll drop the 'k' from Canon Kit Lens and replace it with 'sh'.

pathfinder · January 6, 2005

DavidTO wrote:

Well, we all know the kit lens isn't a great lens, but I got a dramatic example of just how bad when my work bud got the 24-70 2.8L. He's no Fred Miranda, but then again Fred wouldn't bother testing the kit lens.

So here's a not completely scientific comparison of the kit and the 24-70.

All I can say is wow, and from now on I'll drop the 'k' from Canon Kit Lens and replace it with 'sh'.

Dave....

You do not say what aperature these were shot at, nor do you say they were shot from a tripod. L glass really is better than consumer lenses, but this seems worse than most consumer lenses. Is this the whole image or a crop of a frame? Are you SURE the kit lens was focused properly? The whole kit image seems fuzzy to me and it should be sharper in the center than at the corners, wheras improperly focused the whole image is of poor quality.

The image from the kit lens seems worse than I would expect at its better aperatures, say two stops smaller than at its maximum aperature.

DavidTO · January 6, 2005

pathfinder wrote:

You do not say what aperature these were shot at, nor do you say they were shot from a tripod. L glass really is better than consumer lenses, but this seems worse than most consumer lenses. Is this the whole image or a crop of a frame?

The image from the kit lens seems worse than I would expect at its better aperatures, say two stops smaller than at its maximum aperature.

Dan didn't keep a record of the fstop he shot at, he just shot auto, handheld with the flash on.

It's a crop of the edge of the frame. The center is better, but the L glass still far outshines the kit lens.

Perhaps the kit could do better, but I would wager that any of the canon point and shoot cameras would still do better than the kit. Hard to do that scientifically, perhaps, but that image just shows how poor the lens is.

mercphoto · January 6, 2005

DavidTO wrote:

Dan didn't keep a record of the fstop he shot at, he just shot auto, handheld with the flash on.

Auto with flash on probably means the lens is wide-open and at 1/60 second shutter. Could be mild camera shake being part of it. Also, the kit lens won't look very good wide-open, but it is rather reasonable f/8 and lower. I agree though, the kit lens picture doesn't look in-focus.

DavidTO · January 6, 2005

mercphoto wrote:

Auto with flash on probably means the lens is wide-open and at 1/60 second shutter. Could be mild camera shake being part of it. Also, the kit lens won't look very good wide-open, but it is rather reasonable f/8 and lower. I agree though, the kit lens picture doesn't look in-focus.

The center WAS in focus. The drop-off in quality from the center (wish I had that screen grab, too, but he's tossed the files) was amazing. The center was just a touch softer than the 24-70, and lacked some of the contrast, but it was in focus. The edge was dramatically different from the center.

mercphoto · January 6, 2005

DavidTO wrote:

The center WAS in focus. The drop-off in quality from the center (wish I had that screen grab, too, but he's tossed the files) was amazing. The center was just a touch softer than the 24-70, and lacked some of the contrast, but it was in focus. The edge was dramatically different from the center.

Oh! Makes perfect sense now. And I believe it.

pathfinder · January 6, 2005

DavidTO wrote:

Dan didn't keep a record of the fstop he shot at, he just shot auto, handheld with the flash on.

SO we don't really know whether the kit lens was focused as well as the L glass. Nor do we know whether they were shot at the same aperature. And ANY lens evaluation that is done handheld is highly suspect in my mind.

It's a crop of the edge of the frame. The center is better, but the L glass still far outshines the kit lens.

Perhaps the kit could do better, but I would wager that any of the canon point and shoot cameras would still do better than the kit. Hard to do that scientifically, perhaps, but that image just shows how poor the lens is.

As I said, there really is a reason people pay for L glass, but this image from the kit lens seems much worse than I would expect. Many consumer lenses are not up to snuff at their maximum aperature, but sharpen up nicely when stopped down. If for example this was shot at f4, that is very near max aperature for the kit lens, and 1 full stop from max for the 24-70 L. You also need to consider that the periphery of the image may be better or worse at different zooms - wide angle is probably softer in the corners than the tele portion of the zoom range.

This is a jpeg from a Digital Rebel shot hand held by my wife at f4.5 ( wide open for the kit lens) 1/30th ( not the best shutter speed for a lens test) at 31 mm - The original file is available for download by right clicking and changing the L to O. It is vastly sharper than your image I think. Let me know how it compares,Dave.

DavidTO · January 6, 2005

pathfinder wrote:

Certainly looks sharper. Maybe Dan got a bum lens. I'll check out the O file.

pathfinder · January 6, 2005

DavidTO wrote:

The center WAS in focus. The drop-off in quality from the center (wish I had that screen grab, too, but he's tossed the files) was amazing. The center was just a touch softer than the 24-70, and lacked some of the contrast, but it was in focus. The edge was dramatically different from the center.

Think about it this way Dave. The Kit lens is an EF-S lens and ONLY needs to be adequate to the corners of an APS sensor. The 24-70 f2.8 L has to be professionally acceptable all the way to the corner of a 35 mm frame -WAY beyond the edge of an APS sensor - Thus at the corner of an APS sensor, the L glass is a slam dunk, not merely 'acceptable' Makes sense, right??

This is one of the areas of lens testing that is not discussed enough, that is, is it sharp full frame or only on an APS sensor. The Tamron Lenses that I speak highly of, do nicely on APS sensor cameras. Whether they would fare so well in Andy's 1DsMkll is another question.

As lenses get better optically, the call for increasing technical perfection in their usage increases sharply.

As Michael Reichman say in his article about the requirement for a very sharp image, THE MOST critical element is a great tripod, NOT a really sharp lens. ONLY after the camera is stabilized will the sharpness of a really good lens display itself.

fish · January 6, 2005

DavidTO wrote:

Well, we all know the kit lens isn't a great lens, but I got a dramatic example of just how bad when my work bud got the 24-70 2.8L. He's no Fred Miranda, but then again Fred wouldn't bother testing the kit lens.

oh come on, dave. that looks like motion blur on the left. there's just no way the kit lens is that blurry. have your buddy try again.

DavidTO · January 6, 2005

fish wrote:

oh come on, dave. that looks like motion blur on the left. there's just no way the kit lens is that blurry. have your buddy try again.

How do you explain blur on the edges and not the center?

I would bet that if it was an invalid test that more than likely it has more to do with depth of field. I'll have him reshoot a better test on a tripod, and we'll see.

Anyway you slice it, though, I'm glad to be moving on from the kit lens.

Steve Cavigliano · January 6, 2005

A bad copy?

DavidTO wrote:

How do you explain blur on the edges and not the center?

I would bet that if it was an invalid test that more than likely it has more to do with depth of field. I'll have him reshoot a better test on a tripod, and we'll see.

Anyway you slice it, though, I'm glad to be moving on from the kit lens.

David,
Those results are awful. If you're sure nothing funny happened during the testing, then maybe you have a below average kit lens. I sure don't see edge/corner dropoff like you are seeing, with this lens. I get really decent results, with mine, even wide open. No it's not an "L" lens, but then again, I've never seen a new "L" lenses sell for $100

Here's a full sized un-processed kit lens shot, right out of the camera, using Parameter 1. I see a bit of sharpness dropoff in the corners, nothing major, IMO. I thought that this was pretty common with almost every zoom. Maybe I'm missing something, but the results definitely don't look bad enough to chuck the lens. To my old eyes, the results aren't bad at all. It was shot at 39mm's, and F5.6. Maybe wider (18-20mm) would be worse.

http://www.pbase.com/slo2k/image/36088913

I have been touting this lens on other forums as the best sub-$100 zoom you can get. Granted, it's the only sub-$100 Canon zoom you can get.....lol Until it really lets me down, I'm stickin with that story :lol

Steve

jimf · January 7, 2005

DavidTO wrote:

How do you explain blur on the edges and not the center?

I'd have to look at the whole image before I was sure, but it certainly looks like there was significant camera shake in the kit lens shot to me. The lettering shows pronounced double imaging. You can get the kind of effect you're talking about if the camera is rotating; radial velocity is greater on the edges than in the center.

The kit lens can certainly produce better results than seen there. For direct comparisons of the kit and L lenses see http://www.dpreview.com/reviews/canoneos300d/page16.asp. That's more in line with what I've seen myself, although I never really used the kit lens for anything but wide angle.

DavidTO · January 7, 2005

OK, so I've got to eat my words, a bit.

Turns out that Dan's lens is a lemon.

He did a shoot out with his kit lens and mine, and you can see the results below. It's a slice of the full image, taken on a tripod, but the left side of his lens is terrible. That's the portion that my original post was highlighting. He's got a call to Canon to make.

Anyway, here it is. My lens on top, his on the bottom. Both set up exactly the same, both kit lenses, on a tripod, remote activation.

pathfinder · January 7, 2005

DavidTO wrote:

OK, so I've got to eat my words, a bit.

Turns out that Dan's lens is a lemon.

He did a shoot out with his kit lens and mine, and you can see the results below. It's a slice of the full image, taken on a tripod, but the left side of his lens is terrible. That's the portion that my original post was highlighting. He's got a call to Canon to make.

Anyway, here it is. My lens on top, his on the bottom. Both set up exactly the same, both kit lenses, on a tripod, remote activation.

Glad to hear that YOUR lens is OK Dave....Sorry for your pal.

Some lenses are better than others, but the differences tend to be more subtle than the original images you put up ususally. And we all learned a little something about lens evaluations.

AND Lenses CAN BE bad or GO bad and need to be sent in for repair. I would be interested to hear what the repair bill is too.

DigiRebel Kit Lens

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