24-70 2.8 L vs. kit lens...unexpected results?

[davis_edmunds]

<p>Hi all....just bought a second hand EF24-70mm f/2.8L USM. Serial number indicates it was manufactured in 2005. It's feels good and looks well taken care of.<br /> I thought I'd compare it to the lens I got with my 60D, the EF-S18-200mm f/3.5-5.6 IS.<br /> I set up a very quick test...shot the same scene once with each lens both shots at 40/43mm (I eyeballed the zoom setting for the kit lens so it's off by 3mm), 1/160, f11, iso 100, studio flash with my 60D.<br /> Well, these crops seem to tell me there's virtually no difference between the two lenses...in fact I'd give the edge to the kit lens!<br /> I know a lens is about more than image quality...it's also about build and other factors (the 24-70 being faster and constant aperture for instance) but I was kind of expecting at least a mildly notable jump in image quality. Am I off base in my thinking?<br /> If you'd like to see my test, here it is...full shot provided for reference, the crops are full size.<br /> I'd welcome any wisdom/thoughts on the matter. Thanks, D<br>

Image here (I hope it can be viewed full size)<br>

http://imgur.com/DKJhESV</p>

 

[RickDB]

<p>To better appreciate the image quality differences I think you need to compare them wide open. Its hard to differentiate lenses stopped down to f/11; the 24-70 will always win at f/2.8, but try shooting again at f/3.5</p>

[PuppyDigs]

<p>I agree, you'll see little or no difference at F11. In fact, on a 60D you're already suffering reduced IQ due to diffraction. The reason a zoom like the 24-70L costs more is because it's F2.8, has less distortion, is sharper wide open and in the corners than similar lenses and is built like a tank. <br /> <br /> A fair test would be to set each lens at F3.5/24mm, 5.6/70mm and try again. Of course, the 24-70L may need micro adjustment for each individual camera to be at its best. Mine required +5 at 24mm and 0 at 70mm. Most of my lenses need some MA (some more or less on different cameras).<br /> <br /> Or, worse case, you have a defective 24-70L in need of alignment and calibration. My 70-200L drifted out of alignment after a few years of use and needed alignment service to be sharp again.</p>

[peter_c5]

<p>I was interested to read your experience, Dave, as I had a similar experience comparing the 24-105L. I bought a near mint one secondhand, and compared it to my EF-S 18-200, also using a 60D. I too couldn't see any real difference and, despite what Rick and Puppy Face suggest, I did compare the two - using real life photos, not test charts - wide open as well as at f8. I compared at 24mm, 50 and 100/105. My conclusion was that the 18-200 doesn't deserve its mediocre reputation and that for me the full frame lenses only justify their extra size, weight and cost if used on a full frame camera.</p>

[John Crowe]

<p>However the 24-105/4 L does deserve its mediocre reputation. It is convenient for some who use the IS to their advantage.</p>

<p>Yes, retest at f3.5/5.6 and even constant f6.7 across the board and see what happens. When I looked at your images I could identify the 24-70/2.8 L as the better images, even before I checked to see which was which. At f11 they have become quite close though.</p>

[davis_edmunds]

<p>Thanks all...Rick/John, you raise a good point and will retest at varying apertures.<br /> Puppy, I wouldn't be surprised if it could use some tweaking given its' age, I don't know much about what can be done but may have someone look it over.<br /> Peter, I also agree with you that the kit lens might just be better than we give credit...or maybe I happen to have gotten a really good copy!<br /> I admit I have done some commercial shooting with my 18-200, out of necessity, and while it's a slow, noisy beast the images (esp. when shooting with flash and the lens is closed down) look pretty good with a little post work.<br /> My goal in buying the L was to have a faster lens and hopefully help me cut down on the amount of post work needed...we'll see how that goes.<br /> THANKS D</p>

<p> </p>

[dcstep]

<p>When I compare the crops at 200%, I see greater contrast with the 24-70mm and better resolution. It's easiest to see with the first image, showing the printed piece.</p>

[golem_bngolem]

<p>` <br>

<br>

Lesseeeeee ..... a FF lens is being compared to a crop frame<br>

lens on a crop frame camera and no one has so far thought<br>

this odd ? So the FF lens is inferior or "only" equal in IQ to a<br>

crop frame lens ? Gosharootie ! I'm SHOCKED and appalled !<br>

And feeling a more than a bit wooozzeeeieee ....<br>

<br>

Get an adapter and try a Hasselblad lens on a crop frame<br>

camera. What you'll find is that rather than a sooper sharp<br>

26mm center circle [intended for 16X enlargement] thaz<br>

surrounded by a 76mm image circle that can hardly stand<br>

up to a 4X enlargement .... rather than that, you'll find a<br>

76mm image circle that, in its entirety, can easily support<br>

about an 8X enlargement. <br>

<br>

BTW, those ridiculously sharp mural sized prints from 4x5<br>

and 8x10 inch negs ? They were shot with lenses that can<br>

*NOT* ... even if cropped to the very center of the image<br>

circle, the very best region, cannot produce an image thaz<br>

sharp enuf to justify mounting such lens on a 10 year old<br>

12MP digital camera, crop or FF. <br>

<br>

OTOH, the lens on your Smart Phone is most likely waaay<br>

sharper than any megabucks sooper lens from Canon for<br>

FF or crop frame. Said lens cannot cover even 1/4 of the<br>

sensor on your 5D MkIII, but it does have lazer razer IQ ! </p>

 

[davis_edmunds]

<p>"...cannot produce an image thaz sharp enuf to justify mounting such lens on a 10 year old 12MP digital camera, crop or FF"</p>

<p>Thanks for your colourful response Golem ; ) and point taken. Full-frame is the only way to properly evaluate a full frame lens. However, re: your "10 year old" comment, are you thinking I have a D60 instead of a 60D?</p>

<p>THX D</p>