Undecided . . .

[neuroanatomist]

[View:http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=398&Camera=474&Sample=0&am p;FLI=4&API=2&LensComp=675&CameraComp= 474&SampleComp=0&FLIComp=3&APIComp=2]


At comparable focal lengths, I wouldn't really say the 17-55mm beats the 15-85mm at the same distance.

Ahhh, but that comparison doesn't really address the question. As I read it, the question was 'what happens if you take the 17-55mm @ 55mm, and crop the resulting images,' i.e. by a factor of ~1.6 (1.545, actually) to an AoV of 85mm. The answer is basically the same as the APS-C vs. FF issue, cropping will increase your noise and DoF. If taking an image with a shorter focal length and the cropping it was the best answer, no one would buy a supertele lens, they'd all just use a nifty-fifty and crop the heck out of the images, right?!? [:P]

[HDNitehawk]

hmmm, meanwhile, so what happens if i attach my MIR-3 65mm lens to my 7D? it's a wide angle lens when it's on my Pentacon Six, do the lens elves turn it into a wide-angle on my APS-C? or is it a 200mm telephoto? if i put it on a shift adapter for +12mm shift, is it a 77mm lens? :P :P :P :P

The lens elves are not true elves. They are more like leprechauns looking for pots of gold.


The last thing I had them magicaly change is a 100-400mm L they converted it in to a 500mm F L. Thereprice for doing this was about 5000 pot of gold in US currency.

[neuroanatomist]

Was there a rainbow involved in the transaction, Rick?


Back to the OP's issue. Seems like we've taken the simple binary chioce (24-70mm or 24-105mm) and added some complexity (one of those two, or the 17-55mm, or the 15-85mm).


Larry, I think it mostly comes down to the focal length(s) and aperture(s) you want. All four of the above lenses will deliver similar IQ when used on your T1i, so I'd just ignore that as a factor in your decision. In the telezoom range, you have the 55-250mm and the 70-200mm f/2.8L - comparing them, you can see what f/2.8 wil do for you. You have the 18-55mm kit lens, so you know what 18mm vs. 24mm looks like, and you can look back over past shots to find out how much shooting you do in the 18-24mm range. From that, you should be able to determine which of the four lenses is best for your needs. To summarize:

• 24-70mm f/2.8 - normal to short tele zoom range, fast and constant aperture, no IS
• 24-105mm f/4 -normal to mid telezoom range, slower but constant aperture, has IS
• 17-55mm f/2.8 - wide to short tele zoom range, fast and constant aperture, has IS
• 15-85mm f/3.5-5.6 - very wide to mid tele zoom range, slower and variable aperture, has IS

Good luck with your decision!

[HDNitehawk]

Ahhh, but that comparison doesn't really address the question. As I read it, the question was 'what happens if you take the 17-55mm @ 55mm, and crop the resulting images,' i.e. by a factor of ~1.6 (1.545, actually) to an AoV of 85mm. The answer is basically the same as the APS-C vs. FF issue, cropping will increase your noise and DoF. If taking an image with a shorter focal length and the cropping it was the best answer, no one would buy a supertele lens, they'd all just use a nifty-fifty and crop the heck out of the images, right?!?

True it doesn't answer the question specifically. But if the IQ is starting out similar at similar lengths I think we can believe it isn't going to get better cropped it will be worse.Especially with everything that happens to it as you described.


To me the first thing you have to establish is that the 17-55mm is superior to the 15-85mm at an equal length, otherwise you could just crop the 15-85mm at 55mm. From what I see in the charts the 17-55mm isn't beating the 15-85mm at all.


No nifty-fifty, I want to just buy a 14mm L and crop to 500mm. Just think massive DOF everything in focus and you can take a shot of whatever you want and crop later. Finding what I want to crop out might be the problem as it would be so small.

[HDNitehawk]

Was there a rainbow involved in the transaction, Rick?

If it was raining that day in New York City there might have been. If I remember right I ordered it at the end of December, so it was probably icy and cold. It must rain alot in NYC and there must be alot of rainbows, as I have left several Pots of Gold at B&H's doorstep.

[neuroanatomist]

I want to just buy a 14mm L and crop to 500mm. Just think massive DOF everything in focus and you can take a shot of whatever you want and crop later.

Image of a bald eagle plucking a salmon from a river, taken with a 14mm L and cropped to 500mm AoV:
<p style="text-align: center;"]<span style="color: #993300;"].


Note the rich colors, the clear detail.


[:P]

[Jeff Lucia]

I own or have owned...


EF-S 17-55 f/2.8 IS


24-70 f/2.8L


70-200 f/4L IS


70-200 f/2.8L IS Version I


70-200 f/2.8L IS Version II


...and I

[Raid]

Neuro &amp; Dr. Croubie


You are correct and I apologize.


I&rsquo;m so used to converting the FF lenses for a cropped body that I forget that the cropped body values are also converted.


Larry


An apology to you for pushing your post OT.


[:$]

[jolarjos]

I

[jolarjos]

After reading all your suggestions I