yauyi wrote:
I'm curious, any MA adjustment being made to correct close up shot (4~7ft), does this adjustment of the focus plane shift also being magnified in longer distance (15~30ft)?
Since there is only one MA value for a lens Canon recommends that you use your "normal" distance for the lens. If you don't have a "normal" distance they recommend 50X the focal length.
I think it's a mistake to MA a lens to a distance you rarely shoot,
but if you shoot at all distances, it's better to adjust it @ 50x or more
the lenses focal distance, as I believe it tends to be more accurate.
The teathered MA method seems to be most accurate.
Not sure why you meant by 50x focal length? that would be 4250mm??
I have spent couple hours fine tuning the MA today, I had it on tripod and tested it in 1 increment at a time, took 10 shots within 6ft and another 10 shots in 30ft, found out this lens is optimal at +5 instead of +8~15 from yesterday, every time I made the change it wasn't as apparent on close up shots but not sure why it made a significant difference in far distance subject. Right now it's pretty bang on at +5, I'll have to see how it does in the next outing.
Isn't a precision screen more suitable for manual focus?
Kolor-Pikker wrote:
Seeing as you're using a 5D2... you weren't using any points other than the center point, were you? The outer points aren't very reliable, it's probably better just to focus & recompose.
I've now gotten in the habit of using the "sports shooter's" layout with the camera in AI servo and using the AF-on button to focus as it makes the 85L more manageable. Continuous shooting is a good idea too.
And do you have an Eg-S focusing screen as well? The standard focusing screen in most cameras lets you see the effects of DoF only down to f/2.5, so a percision screen is very recommended for fast primes, especially the 85L....Show more →
My first copy of that lens focused well at short distances, but was unsharp at 10 yards and more. No FF, no BF, just blurry. If the sharpness drops with distance, you may have the same issue. Some of your pictures look front focused to me though. Perhaps it is time to shoot some brick walls and batteries...
Isn't a precision screen more suitable for manual focus?
Probably, but I have one installed even though I don't often use MF w/ the 85LII
It's much more reassuring to actually see your DoF when AFing, and you can adjust it if it didn't quite hit the mark.
For Portraits, I don't even try to use 1.2 to 1.6 on this lens...it's a hit or miss for me.I make sure I get them on focus.
I guess it takes some experience to use wide open.
reedtess wrote:
For Portraits, I don't even try to use 1.2 to 1.6 on this lens...it's a hit or miss for me.I make sure I get them on focus.
I guess it takes some experience to use wide open.
wow
i always use 1.2, for close ups and many times for distance as well.. focus is razor sharp unless user error.
im surprised people are having issues with this lens, of all lenses.
I've also noticed that above aperture 2 or so, the sharpness kind of remains the same.. so unless i need more DOF theres really no point going any smaller.
just my 2 c. This is an awesome lens, one that keeps me tied down to the Canon system.
epuja wrote:
im surprised people are having issues with this lens, of all lenses.
i'm not [surprised]. with such a narrow DOF (at f/1.2), relatively slow AF, and the usual errors (mis-calibration, user, etc), this lens can be quite challenging.
yauyi wrote:
Shot like #1 and 2 i get about 50% keeper, and #3, 7, and 8 plummeted down to 10~20% keeper those like 5, 6, and 9 is about 75% which is acceptable I think.
Sound like my 5d2 and 35L/50L/85L. Uneven light with fast lenses make 5dseries AF goes crazy.
After having both the MK I and MK II, I prefered my MK I better. Go figure. The AF sucks, so I expected that. Mine stayed in MF.
If you have never had one of these lenses, keep shooting with it and report back in a month or so. My friend, who is a much much better photographer than me, occasionaly used it and he "hated it." I truly think that is because he didn't get to spend time with it.
My experience with the 85L (have used it for many years) is that it has some field curvature, meaning the plane of focus is not perfectly flat. It tends to focus a bit closer at the edges than the center. So if you're using the center focus point and recomposing, you might find that the middle of your photo is focused but the extremes (like where a subject's face might be) are slightly soft.
Look here: http://www.slrgear.com/reviews/showproduct.php/product/354/cat/10 and click on Full-Frame Results. Click on the graph to open it in a new page and move the aperture slider. You'll see that wide open the lens is sharp in the middle, but falls off to the edges, my guess being in part due to the field curvature. The lens can be focused sharply off-center, but you'll need to do so with a non-central AF point of try to manually focus it. My suggestion would be to try live view at 10X (a pain to do hand held, but still doable). The only catch with live view is that with very fast lenses the camera will stop down the lens in bright light to moderate the amount of light reaching the sensor. The way to prevent this is to either use depth of field preview for your actual shooting aperture, or change live view to movie mode, where it is forced to work at the actual shooting aperture *but* this is only if you set exposure manually (these instructions are based on using live view on a 1DIV, which I expect to be the same as the 5DII, but might not be).
I would highly recommend you look into the Eg-S. I found it made a huge difference back when I first got the lens and was working with the 1DII series. That stock screen would smear the image too much but I could easily discern accurate focus with the S screen. The S screen will result in a darker viewfinder image with slower lenses but IMO it's still OK at f/2.8 but f/4 will be fairly dim. Not a problem outside, but could be inside. One other catch I've heard is that the 5D series may not be as precisely set-up for accurate manual focusing and might require calibration by shimming the focusing screen... but it's worthwhile for you to try the screen first to see if it helps.
It definitely helped me, but mostly for closer working distances. For full length type shots I still had trouble (could be my eyes) and find the most accurate solution is 10X live view.
according to the DOF calculator, 15ft @f/1.2 I'd get 0.67ft DOF....which is significantly greater than at 5ft subject distance with only 0.07ft DOF......Show more →
It's DOF, not critical point of focus. There is a difference. And as I've mentioned, the lens seems to have a bit of field curvature that could pull the plane of focus away from the subject.
those like 5, 6, and 9 is about 75% which is acceptable I think.