ok, some people will probably jump me for this... but...
in Sam's backfocus examples etc., how do you know what the camera thinks is acceptably sharp enough to consider it to be "in focus"? I know everyone wants the camera to nail focus precisely, but since that isn't even what it's trying to do... shouldn't we have a clear definition of the camera's working tolerance and determine if it is working to within that? I'm assuming Sam's camera returned a focus confimation, right?
I know I've personally taken issue with common DOF calculations, obvious to me even in film days before pixel peeping became so easy... built into the estimates is the assumption of what is "acceptably sharp" and if you don't agree with that... it isn't.
Just walking around with the 1Ds2 and 50L this evening. Not a special composition shot, but representative of what I think is a decent low light shot. Exif is stripped after resizing in CS2, but this was at f/1.8, 1/50th, ISO 1000. Autofocus. Monopod. Illuminated with High Pressure Sodium lights, so the white balance is wigged out.
Nill, I cannot really make a reliable comment on the focus speed, because I seldom ever shoot anything that needs great speed. Perhaps others can comment.
Okay, finally got the chance to do some tests. Real world pics look pretty good. But when testing back/front focus, it's way off. At f1.2, dof is so shallow that focus seems to be pretty much on. When stopped down, back focusing is very apparent. I don't know yet if i'm going to return it or drive it down to canon irvine to get fixed. Good news is that when i tested my 24-70 wide open for comparison, it was tack sharp and focus was spot on.
HEY CANON ARE YOU LISTENING?
WHY MAKE YOUR CONSUMERS ASK THEM SELVES THIS QUESTION?
joecirca79 wrote:
Okay, finally got the chance to do some tests. Real world pics look pretty good. But when testing back/front focus, it's way off. At f1.2, dof is so shallow that focus seems to be pretty much on. When stopped down, back focusing is very apparent. I don't know yet if i'm going to return it or drive it down to canon irvine to get fixed. Good news is that when i tested my 24-70 wide open for comparison, it was tack sharp and focus was spot on.
Nill Toulme wrote:
Sam, how did it go with the rollergirls? (The lens I mean...)
The bout is tonight, I'll try to post when I get back afterwards.
Don't know if you missed it, but somewhere along the line I compared the 50/1.2L's speed being a bit slower than the 35L (which is not fast to begin with). So, again... it's definitely not a fast focuser, but I don't think it's problematically slow. But needless to say a lot of this depends on how close you are to your subject, etc. I've bought the 50L to do full length action shots, like this:
85/1.8, probably around f/2
So the lens isn't going to have to work as fast as if I wanted to do tighter shots (which is what I will be using the 85/1.8 for):
85/1.8, probably around f/2
Sorry to introduce non-50L shots here, but it's something to keep in mind. For tight action shooting with an 85 I would be much more critical of focusing speed. I think with the slightly wider stuff I'll be doing with the 50 it will be fine.
I have shots from my birthday party last night and they look pretty damned good. Unfortunately we're rushing to get out of the house so a Real Estate agent can show it (second showing, keep your fingers crossed!) but if we hit a Cafe with a wireless connection I'll try to through some up.
andyyau wrote:
Canon AF system has problem under fluorescent lamp lighting. Please try other light sources if it is the case.
If you were referring to my back focus shots, it was shot under bright halogen. I took multiple shots and they all pretty much turned out the same. I'm returning the lens monday and hoping that the next batch will be problem free.
As for AF speed, i did a quick comparison between the 50L and 24-70L. Same distance, both at f/2.8, with the lens set at infinity under the same light. The 24-70L locked on a tad quicker.
So... brief update before I head to the bout... reviewed the photos from last night, and it looks like nearly all the shots are backfocused to a certain degree. Major bummer.
John Black answered the chopped highlight circles yesterday...2 pages ago.
"Another factor is any lens faster than F2 will have chopped bokeh circles. The top of the chamber and floor truncate the opening. Just look through the front of the 85L such the viewfinder illuminates the opening. You'll be able to see the top and bottom of the mount openings chopping the circle. Again, this has nothing to do with the 50L, it's the opening to the chamber."
John Black answered the chopped highlight circles yesterday...2 pages ago.
"Another factor is any lens faster than F2 will have chopped bokeh circles. The top of the chamber and floor truncate the opening. Just look through the front of the 85L such the viewfinder illuminates the opening. You'll be able to see the top and bottom of the mount openings chopping the circle. Again, this has nothing to do with the 50L, it's the opening to the chamber."
But I disagree with this. In my findings, the Canon 50 f/1.4 does not produce the chopped highlights:
John Black answered the chopped highlight circles yesterday...2 pages ago.
"Another factor is any lens faster than F2 will have chopped bokeh circles. The top of the chamber and floor truncate the opening. Just look through the front of the 85L such the viewfinder illuminates the opening. You'll be able to see the top and bottom of the mount openings chopping the circle. Again, this has nothing to do with the 50L, it's the opening to the chamber."
Still leaves open the question of why the 50/1.2L shows the chopped circle problem and the 50/1.4 doesn't. I haven't seen the chopped circles consistently, so I'd be curious to know where it's a problem - is it only a problem when focusing close to subjects, etc.
We're sorting out a card-swapping snafu here, but hopefully I'll have some samples up from the bout before I hit the sack. So far it looks like the 50L did very, very well shooting Roller Derby. I didn't shoot wide open much since I was instantly seeing birefringence - which is to be expected with the subject matter (one of the teams had black and white stripped uniforms) and so I just stopped down a bit to keep it in check. Most of the shots were at f/2 or f/2.2, maybe f/4 if I was grabbing a portrait.
Focus speed wasn't an issue generally - tracking was spot on, even for some close dives to the camera. The only real problem I had is when I accidentally AF'd off the subject to the background - pulling it back to the subject is, frankly, painfully slow. Luckily this only happened a couple times. It's a bummer, but pretty minor in the scheme of things.
Being able to shoot with a 50mm in these conditions was fantastic. It allows me to be on top of the action (and in front of the referees, which is a constant battle) but still get full length shots. The lens has slotted in right where I was hoping and so far it looks like performance wise it fits the bill.
Again, sorry I don't have any photos yet, I'll try to have some up tonight.
Good tests, though I don't think that his verbal review exactly matches what I'm seeing in a couple of the test images. In the "tin soldier" shot, it appears to me that the 1.2's plane of focus is a bit behind the beard whereas the 1.4 is about right on the beard hair. The loose hair strands to the right of the soldier's face are sharper on the 1.2 than on the 1.4.
Also, I don't agree with his verbal commentary on the "fringing" on the 1.2's bokeh. It's certainly a smoother bokeh than the hard edge of the 1.4's wide open, but I wouldn't confuse the diffused edge (even with color separation) of the 1.2 with the fringing that is related to ordinary chromatic abberation. What I would call this a deliberate designed 'softening' of the edges of the bokeh. This lens appears to have been designed to produce nice smooth edges to the OOF highlights, and that design shows in the much smoother rendition of the out-of-focus lights in the image compared to the 1.4.
Sam Bennett wrote:
... So far it looks like the 50L did very, very well shooting Roller Derby. ...Focus speed wasn't an issue generally - tracking was spot on, even for some close dives to the camera. ... The lens has slotted in right where I was hoping and so far it looks like performance wise it fits the bill.
Well darn — just when I was thinking I could let this one go. :-(
The only real problem I had is when I accidentally AF'd off the subject to the background - pulling it back to the subject is, frankly, painfully slow. Luckily this only happened a couple times. It's a bummer, but pretty minor in the scheme of things.
I wonder if one could train oneself to yank it back into the right range with a quick manual adjustment?
