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Author Topic: Crop sensor with 'full frame' lens?  (Read 8937 times)

spidermike

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Crop sensor with 'full frame' lens?
« on: July 26, 2008, 12:08:28 pm »

I have the Canon 30D camera and am looking to buya zoom lens going 17mm and up (with top end being between 50mm and 85m). I want to get as good a quality as I can afford and this will include some lenses designed for full-frame cameras.

Obviously one of the performance criteria for a lens is its edge resolution but with a lens designed for a 'full frame' sensor I presume this is less of an issue because the 30D's crop sensor will not pick up that part of the image where it is most evident.  I presume that this also applies to the amount of visible edge distortion.  
So does this put competitor lenses (e.g. Canon vs Sigma vs Tamron) on a more level playing field than the reviews would suggest (presuming such reviews were done on a full-frame camera)?

If I were to go for a lens designed for crop sensors then obviously edge resolution and distortion would certainly be one of the criteria.

Any advice welcome.

Mike
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Panopeeper

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Crop sensor with 'full frame' lens?
« Reply #1 on: July 26, 2008, 01:58:26 pm »

The Canon EF-S 17-55mm f/2.8 IS is the very best you can get from Canon, Tamron or Sigma. It rivals the EF 16-35mm Make II, as well as Canon primes in that range.
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Gabor

spidermike

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Crop sensor with 'full frame' lens?
« Reply #2 on: August 14, 2008, 10:23:18 am »

Thanks, Panopeeper

That is certainly the lens I have my ey on but I am trying to balance the cost against cheaper options from Sigma etc.
Keep saving them pennies, I guess.
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Panopeeper

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Crop sensor with 'full frame' lens?
« Reply #3 on: August 14, 2008, 01:50:09 pm »

According to reviews and several customers, the Tamron 17-55mm is a very good lens (some of those, who have it are claiming that it rivals the Canon 17-55mm), and much-much cheaper, but without IS. If IS is useful in your photography, then try to go for it; however, it may not be of importance for you (shooting moving objects, shooting much from tripod).

There are several areas I am not perfectly happy with the Canon EF-S 17-55mm IS:

1. strong CA (not alway correctable in ACR),

2. strong vignetting (this is a curse with panoramas, though it could be corrected in ACR if I made a one-time huge effort to evaluate the required adjustments at different apertures and focal lengths),

3. it is the sharpest @ f/5.6. This is good sometimes, but in landscape, when I shoot from tripod and want to increase the DoF, the loss of sharpness is noticable already at f/11 (this is not diffraction yet!), the smallest aperture I dear to use is f/13. From there diffraction rules anyway.

Still, my best lens before, the 50mm f/1.4 has been unused since I got the 17-55mm.
« Last Edit: August 14, 2008, 01:51:54 pm by Panopeeper »
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Gabor

fike

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Crop sensor with 'full frame' lens?
« Reply #4 on: August 14, 2008, 02:05:10 pm »

Quote
I have the Canon 30D camera and am looking to buya zoom lens going 17mm and up (with top end being between 50mm and 85m). I want to get as good a quality as I can afford and this will include some lenses designed for full-frame cameras.

Obviously one of the performance criteria for a lens is its edge resolution but with a lens designed for a 'full frame' sensor I presume this is less of an issue because the 30D's crop sensor will not pick up that part of the image where it is most evident.  I presume that this also applies to the amount of visible edge distortion. 
So does this put competitor lenses (e.g. Canon vs Sigma vs Tamron) on a more level playing field than the reviews would suggest (presuming such reviews were done on a full-frame camera)?

If I were to go for a lens designed for crop sensors then obviously edge resolution and distortion would certainly be one of the criteria.

Any advice welcome.

Mike
[a href=\"index.php?act=findpost&pid=210835\"][{POST_SNAPBACK}][/a]

I believe that your general hypothesis is correct, although there are good lenses that are optimized for the cropped sensor--the canon 17-55 f/2.8 IS is a notable example.  

If the characteristics of a lens are such that its quality suffers along the edges, a cropped sensor camera will get better results than a full-frame sensor.
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Fike, Trailpixie, or Marc Shaffer

mahleu

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Crop sensor with 'full frame' lens?
« Reply #5 on: August 14, 2008, 04:37:34 pm »

1 vote for the 17-40L
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Misirlou

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Crop sensor with 'full frame' lens?
« Reply #6 on: August 14, 2008, 04:39:06 pm »

DxO can take care of the C/A and distortion from the 17-55 EF-S pretty much completely. I wouldn't be surprised if DPP can do pretty much the same, although trying to handle it in LR/ACR may not be ideal.

In any case, since I got my 17-55, I use it way more than I expected to. Between f2.8 and IS, you can take some amazing low light shots. Sharp as heck too.
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The View

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Crop sensor with 'full frame' lens?
« Reply #7 on: August 14, 2008, 05:34:20 pm »

The 17-55/2.8 IS from Canon is an excellent lens, and I would not go with third party.

I also read the rave review on the Tamron, and I found plenty of reports on the web that Tamron's quality control is not good. There are plenty of really bad copies out there.

And don't forget IS.

Just one thing: put an UV filter on the Canon lens right when you buy it (most photographers do that anyway). Otherwise, the lens will suck in dust through two tiny vents.

I recommend the B + W UV haze filter. Costs about 77$. Worth it. Excellent quality.
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DarkPenguin

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Crop sensor with 'full frame' lens?
« Reply #8 on: August 14, 2008, 05:49:23 pm »

Quote
I also read the rave review on the Tamron, and I found plenty of reports on the web that Tamron's quality control is not good. There are plenty of really bad copies out there.
Have you personally experienced this?

People whine about canon's QC, too.

Quote
Just one thing: put an UV filter on the Canon lens right when you buy it (most photographers do that anyway).
They do?
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DarkPenguin

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Crop sensor with 'full frame' lens?
« Reply #9 on: August 14, 2008, 05:51:41 pm »

Quote
I recommend the B + W UV haze filter. Costs about 77$. Worth it. Excellent quality.
[a href=\"index.php?act=findpost&pid=215066\"][{POST_SNAPBACK}][/a]

Make sure it is the MRC version.
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ErikKaffehr

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Crop sensor with 'full frame' lens?
« Reply #10 on: August 14, 2008, 09:23:46 pm »

Hi,

Can you explain? Common wisdom is that diffraction causes loss of sharpness at some aperture, where the optics become diffraction limited. Is there any aberration which increases with aperture?

Best regards
Erik


Quote
3. it is the sharpest @ f/5.6. This is good sometimes, but in landscape, when I shoot from tripod and want to increase the DoF, the loss of sharpness is noticable already at f/11 (this is not diffraction yet!), the smallest aperture I dear to use is f/13. From there diffraction rules anyway.


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Erik Kaffehr
 

ErikKaffehr

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Crop sensor with 'full frame' lens?
« Reply #11 on: August 14, 2008, 09:31:18 pm »

Hi,

I had severe decentering issues on a Tamron 17-50/2.8 and a Minolta 17-35/2.8-4 made by Tamron. I also have a Minolta 28-75/2.8, also made by Tamron, which is excellent. My replacement for the 17-50/2.8 is OK.

My suggestion is:

- Buy your lenses at good dealer
- Test immediately after purchase
- Return lens if there is a big difference in sharpness between corners.

You may check the Sigma 18-50/2.8, too.

Erik


Quote
Have you personally experienced this?

People whine about canon's QC, too.
They do?
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« Last Edit: August 14, 2008, 09:34:10 pm by ErikKaffehr »
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Erik Kaffehr
 

Panopeeper

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Crop sensor with 'full frame' lens?
« Reply #12 on: August 14, 2008, 11:06:01 pm »

Quote
Can you explain? Common wisdom is that diffraction causes loss of sharpness at some aperture, where the optics become diffraction limited. Is there any aberration which increases with aperture?
Lenses do have their "sweet spots", where they are the sharpest; this is usually far from the point, where diffraction sets in. Several of my lenses are the sharpest around f/8. The sweet spot of the EF-S 17-55mm is at or below f/5.6, thus it is rather the exception. It is good in low light, but vignetting and DoF force one to use a smaller aperture.
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Gabor
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