zhangyue
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 p.34 #15 · Pre-order: Sigma 24mm f/3.5, 35mm f/2 and 65mm f/2 DG DN lenses | |
j4nu wrote:
I'll chime in on the AF accuracy of 45mm debacle, as I grabbed this lens during BF sale (that was the only offer that caught my eye and I also wanted to see for myself how AF-C is in practice, because the opinions ranged from unsuable to completely okay).
So, in my limited testing on A7III of AF-C vs AF-S in range of 0.5m (that's where the wide open glow gets less noticeable imho) to a couple of meters maximum I came to the following conclusions:
* AF-C is simply unreliable, I'd say in 9/10 cases AF-S gives noticeably better focused image. I don't have any other lens that behaves like that (some actually seem sometimes worse in AF-S).
* AF-C is still usable (45mm @2.8 is not that demanding even around 0.5m), but the chance you will have tack sharp image focused exactly where you wanted (e.g eye via eyeAF) is small (but we're talking mostly about pixel peeping at 100%). I took a lot of pictures in AF-C, that are worse than AF-S but still completely usable to me. The thing is you don't know when taking the shot how close (or far) AF-C precision will be compared to AF-S
* AF-C + slow/mid continuous drive is now the only way I use AF-C, so instead of taking 1 shot I take around 3-5, which in most cases gives me at least one focused "close enough" to AF-S.
* AF-S is too slow to use with my kids  , so I hope Sony improves AF-S operation in next iteration of cameras (as I've read about other cameras) . What I mean, in most cases it's easier to take multiple shots in AF-C hoping at least one will be good enough, than to wait for the long enough "still" moment when AF-S manages to acquire focus.
So, to sum it up, I'd say AF-C is usable but luck is involved (i.e. you need some means to minimize its impact) ...
Maybe an example of AF-C (click the link to view the original size), shot at about 0.8m wide open, 3 shots exif claims one second apart from each other, taken from 100% crop, eyeAF I hope:
https://live.staticflickr.com/65535/50716502623_47bef4dadf_h.jpgAFC_1sec_series_100 by Jan U, on Flickr
So, to me they are all acceptable, with the first being the worst, but none of them is really tack sharp on the eye (actual focus is rather on the eye lashes and still not perfect)... For this kind of shot, this is an acceptable result for me though  ....Show more →
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That is all acceptable to me if they are meant to be family images. I think there are so many important factors ahead of the sharpness for image like these. Lighting, story, composition, face expression etc.. and people know me know that I will put background rendering in front of sharpness difference with case like these 
chez wrote:
Yes, everyone has different requirements for focus and what might be ok for one just does work for another. For me, this lens would be used to photograph subjects that move and I love using eye-AF for these conditions. If the focus is unreliable then it really does not matter how good the rendering is if the focus is missed.
Most images I see with this lens are of stationary objects where it shines...but for moving subjects it just might fall short.
I'm back to looking at the Batis 40 as I love what I get from the 25 and 85.
I don't really know your situation and requirement for lens like this. and I have zero doubt about rightful decision you made with which tool is best suit for you. At the same time, I have no doubt about my decision or others' who love this lens.
Per our FMer friend @darrellc
it is just what you have to do with certain equipment if you want the benefits, like with this lens.
I am sacrificing super fast AFC for other things I value higher personally. In this case, build, rendering and size. and I made my choice not even for lens but camera as well. I don't pick the easiest one but most enjoyable one (or suitable one for me anyway)
here is one link I want to share with FMers who like or want to know more about this lens. I don't even know this guy much, not famous anyway. This whole set was made with Sigma FP and 45mm lens and using JPG out of camera only and mostly WO. After having FP for only 3 days, I know how UN-capable this camera AF is, but I also learn how enjoyable this camera can be and how capable it will be if I try to work with it.
Do we feel images in above link are not sharp enough to appreciate or some will benefit from better AF to make them higher level artistically? The tool may not help me to capture running human or animal toward me, but it certainly help me to disappear on the street and hunting for perfect opportunity and give absolutely neutral looking images real to eyes.
Anyway, food for thought.
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