Settle a bet...

[Tofu_Girl]

Hi everyone, I'm hoping someone here can settle a bet for me.

So I'm over at my friend's apt and he's playing with my 50mm f1.8. After about 20 or so shots...he uploads them to his computer and we notice the pics taken at 1.8 to be a little soft. So we decided to take some test shots after I mentioned his hands always seem to be shaky when around me...(he didn't enjoy that too much http://forums.clubsnap.org/images/cs/smilies/wink.gif)

We took pictures of his crumpler bag with the focus centered right on the logo. The pictures were taken on a tripod...The picture taken at 2.8 was taken with AI Focus...the lens was then changed to MF so that no focal change was done before taking the 1.8 pic. Full Sized pics shown below...

http://www.i-levelmedia.com/test/crumpler_1.8.JPG (http://www.i-levelmedia.com/test/crumpler_1.8.JPG)
http://www.i-levelmedia.com/test/crumpler_2.8.JPG (http://www.i-levelmedia.com/test/crumpler_2.8.JPG)

The pics to me seem to be what you'd expect...a little soft at 1.8 but much sharper at 2.8.

His contention is that the pictures are equally sharp but at a different focus point...basically saying the AF on the lens is a little off. So even though we centered focus on the logo, he seems to think the orange lining on the top right is in focus and equally sharp on both pics. I think he's full of crap personally...and can't admit being wrong.

What do you ppl think? http://forums.clubsnap.org/images/cs/smilies/smile.gif

Also...how are other ppl's 50mm 1.8's out there? Should the picture we took be sharper at 1.8?

[Curtis N]

Should the picture we took be sharper at 1.8?I'm certainly not the greatest lens expert here, but almost every book on basic photography says that most lenses are sharpest one or two stops down from wide open.

This lens, apparently, is no exception.

[mrclark321]

I took both pictures and put them side by side and focussed on the Crupler logo.
You can really tell that it is sharper at 2.8

Dan

[mrclark321]

Do what I said, open both photos at the same time and expand them. Show them to your friend side by side, It's a no brainer!!

Dan

[Bob_A]

The 2.8 image is definitely sharper, but not by as much as looking at the crumpler logo would suggest. To me the point of focus is in front of the logo somewhat for both photos. It's hard to tell by how much, but it could be by about an inch.

So there ... I think you're both right. Now show us some pictures that he takes hand-held when you're around him and we'll confirm your theory about shakey hands. :)

[Leorooster]

... almost every book on basic photography says that most lenses are sharpest one or two stops down from wide open.

This lens, apparently, is no exception.

Agree with Curtis. I only took a glance, but already noticed that the 2.8 one is much sharper than the 1.8 one.

[tim]

I'd say it's generally sharper at F2.8 than at F1.8, rather than there being a difference in the focal point.

[Tofu_Girl]

thanks all...

I'm going to run a test at home later with a ruler to test for any front focusing at 1.8

:)

[martook]

Well, I can't really tell any difference, since that probably is the slowest webserver I've been trying to access like... ever.
But as people are saying, there is nothing strange about the lens being sharper at 2.8 compared to 1.8, even the L-lenses seem to have this "problem", and here we're talking about the smallest, cheapest lens in the Canon line-up... so not really that surprising, is it?
The 50mm 1.8 has a reputation of having a pretty bad AF by the way, so that could always be a problem, but until I've seen the pictures I can't really say for sure what I think about his idea...


Seems like you're new on the block by the way... if that's the case, let me be the first to say:
Very very welcome to the most expensive free forum on the net! :D

[condyk]

The 50mm 1.8 has a reputation of having a pretty bad AF by the way, so that could always be a problem, but until I've seen the pictures I can't really say for sure what I think about his idea...

That's funny ... for £60 mine AF's like a real champ. I even like the buzz it makes, as if it's really trying hard to become an L lens :lol: Compare it to my Sigma 100-300mm HSM and maybe I'd have a slight question mark, but that's around 14x the price!

As to focus the f2.8 is sharper. I think the images are being served via an old hand cranked computer!!!!

Hey don't worry about who's right ... you can always kiss and make up :lol: :lol:

[Cadwell]

The f/1.8 image is softer than the f/2.8. There's also more CA. That's what you would expect from the EF 50mm f/1.8. Some exceptional lenses manage to remain sharp even when wide open. The 50mm f/1.8 isn't one of those. It's a very good lens for the money, but that's as far as it goes.

[martook]

That's funny ... for £60 mine AF's like a real champ. I even like the buzz it makes, as if it's really trying hard to become an L lens :lol:
Well, for the price, the AF is probably better than anything else on the market :D
Compared to the 1.4 USM version though, the AF is supposedly not too good, but that's just what I've read, I don't own either lens ;)


I think the images are being served via an old hand cranked computer!!!!
Haha, yeah... or the ISP couldn't afford anything better than a 14.4k modem!

100%[====================================>] 4,258,422 1.93K/s ETA 00:00

Now that's just sad...

[ron chappel]

So we decided to take some test shots after I mentioned his hands always seem to be shaky when around me...(he didn't enjoy that too much http://forums.clubsnap.org/images/cs/smilies/wink.gif)


Hahahaha. He's hot for you! :D :D