p.2 #2 · So what's the deal with AF on the FE 28-70?
mmurph wrote:
^^ Interesting. Thanks!
Was the focus better if you switched to Continuous focus? That obviously eliminates the ability to focus and recompose, but ...
I haven't tried Continuous with back button focus on the A7 as I had no luck with it assigned to the shutter release. I'll have to try again sometime. On my Nikons I've always used AF-C assigned to the back button and as long as my lenses have been dialed in, I find it to be the best method on those cameras.
p.2 #3 · So what's the deal with AF on the FE 28-70?
I have found the same thing about Continuous Focus on my Canon's.
I use it almost all of the time now on my Canon 7DII (I sold my D7100 when the 7DII came out. Now I wish that I could buy a D750.) .
The 7DII has 65 all-cross AF points, and good coverage of the full frame. I can pick the exact point for the composition that I want, even in low light, and place that on an eye or similar. It is wonderful for events where I am shooting wide open in low light, or portraits with a large aperture and shallow depth of field. Plus wildlife of course
It seems like the same process should work with the A7's and Contrast Detect AF. I was just reading this last night from Roger Clark:
Contrast Detect Autofocus uses the sensor for autofocus using a contrast detection method (CDAF). The lens is moved, the sensor read out, and the contrast checked, the lens moved, the sensor read out, the contrast checked and if it is getting better keep moving in that direction, if not, go back, hunting for best focus. Each readout can take tens of milliseconds and because multiple readouts are required to hunt for focus, focus can take a large fraction of a second or longer.
So in theory, the A7 should continue to refine it's focus selection. At least, to the limit of it's tolerance. Obviously it is a bit more complicated in practice. I wish that my A7II had the A6000 auto focus! Some day - and then about 1 year later I will be able to afford it.
(I can't believe that the A7S is still so expensive!)
p.2 #4 · So what's the deal with AF on the FE 28-70?
While I liked the 28-70 (for its price, size, decent optics and OSS) I too found the focus issues pretty annoying. I'm okay with low light shots turning out soft, but shooting a landscape in good light should be in focus if the camera confirms focus. One can certainly do critical MF work, but I'm talking more about when your just out on a walk etc. Should be able to stop, take 5 seconds, and take an in focus shot with high confidence its going to be sharp.
Ultimately, I found that 90% of my shooting was at 28mm anyways with the lens, and the other shots at 50mm or so, where the lens really doesn't have the subject isolation I want, so I ended up selling mine.
Plan to replace it with the 28/2 FE, which should be every bit as good at 28mm, not to mention faster, and with better bokeh quality (for a wide) all the while not really adding any extra size/weight.
Too boot, it would allow the 21mm equiv UWA conversion adapter which looks pretty good for the money.
p.2 #5 · So what's the deal with AF on the FE 28-70?
Another thing to check is make sure the FE 28-70 has the latest firmware update of 02 and not 01. This is not obvious, and I have just updated my FE 28-70 the other day.
p.2 #6 · So what's the deal with AF on the FE 28-70?
I know this is an old thread, but having just purchased a copy of the lens being discussed, I'm curious about this weird focus effect.
So, Jordan, what was the final disposition of this matter for you? Did you keep it, or sell it off?
After mine arrives, I'll certainly be checking it closely on the a7R. My hopes are it will be a good casual lens for outings and maybe family and friends. We'll see!
Anyone else have any pro/con experiences with the 28-70 FE focusing?
p.2 #8 · So what's the deal with AF on the FE 28-70?
I notice similar things with my a7r and the 16-35mm at the 35mm setting. When automatically focused, the edges can be soft. When manually focused, the edges are very sharp, but the focus distance indicator doesn't say infinity, it'll say like 5-10m. I have tried wide area AF and single point, while single point works a lot better it's still not quite as good as manually focusing, but this is only for like true infinity distances. Odd behavior, I'll see if I need a firmware update perhaps
