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04-30-2013, 08:34 AM - 1 Like   #31
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Here is a picture of what happens when you use the center focus with a shallow depth of field, lock focus, then recompose.
The lines from the focal plane are all the same length. The break in the line represents the current depth of field. I have extended the depth of field from the original center focus, where presumably the subject is placed. When recomposing, the subject distance to the focal plane shifts, but the depth of field does not.

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04-30-2013, 08:48 AM   #32
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QuoteOriginally posted by JimJohnson Quote
I'll take a stab at justifying using the AF center point and recomposing.... My first thought is if the lens is significantly sharper in the center than the edges. Personally, I am unlikely to routinely use a lens with this much center to edge difference. My second thought is if the scene has too many distractions to use multiple AF points and speed is critical, center focus and recompose will on average put the subject's framing equi-distant from the focus point.

Now the big limitations- if metering is locked in at the same time as focus, exposure may be adversely affected. And the real biggie, recomposing after focusing will always change the subject to sensor distance. This is no big deal if the depth of field is adequate. But with a shallow depth of field like the circumstances shown in this thread, you are just asking for trouble.
Thanks Jim. I appreciate the well thought out responses.

I am just going by my own, rather limited compared to many of you, experiences. For my own style, I have found the select AF points to be quite a bit more accurate. However, with experience I have gotten fairly decent at manual focus and use it quite a bit in these sorts of circumstances. I would not hesitate to use center point/recompose if I was in a situation where I had to be lightning quick, though. Better to get a shot than miss it completely!
04-30-2013, 06:37 PM   #33
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Despite getting lots of shots out of focus I did get some nice ones in focus. I love this lens. (taken with FA 77mm 1.8 limited)
Note: color looks a bit off here, but on my monitor its perfect.

04-30-2013, 07:24 PM   #34
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You've stopped down just a bit in this last photo and it shows in the extra depth of field that you've got.

Just for fun I try to catch my toddler using my Tak 50/1.4 using whatever natural light is around - so I usually can't stop down at all if I want to keep the ISO down. This is more of a challenge than an attempt to get great photos, and is also about learning about how the lighting will work on an image. Anyhow, even if I get the focus spot on his eyes, and neither he nor I move before I take the shot, I'm lucky if the eyes are sharp, and if they are, very little else is. I've seen a few discussions about 50mm lenses (whether 1.4 or 1.7) where the reviewers talk about the lens being sharp by 2.0 or 2.8. So just stopping down that little bit is going to make a world of difference, and also mean the focusing doesn't have to be exact.

04-30-2013, 07:48 PM   #35
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QuoteOriginally posted by MSL Quote
You've stopped down just a bit in this last photo and it shows in the extra depth of field that you've got.

Just for fun I try to catch my toddler using my Tak 50/1.4 using whatever natural light is around - so I usually can't stop down at all if I want to keep the ISO down. This is more of a challenge than an attempt to get great photos, and is also about learning about how the lighting will work on an image. Anyhow, even if I get the focus spot on his eyes, and neither he nor I move before I take the shot, I'm lucky if the eyes are sharp, and if they are, very little else is. I've seen a few discussions about 50mm lenses (whether 1.4 or 1.7) where the reviewers talk about the lens being sharp by 2.0 or 2.8. So just stopping down that little bit is going to make a world of difference, and also mean the focusing doesn't have to be exact.
The image above was taken at f-stop 2.5 fyi!
04-30-2013, 07:58 PM   #36
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QuoteOriginally posted by SashasMom Quote
The image above was taken at f-stop 2.5 fyi!
Yup - I knew that because I had checked the EXIF data before posting. What I didn't do is go back to your original post, although I had recalled at some stage the discussion was about using the lens closer to its maximum openings. But it's late at night for me, so I can be ignored - same as any other time of the day.
04-30-2013, 08:38 PM   #37
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QuoteOriginally posted by Sandy Hancock Quote
Hmmmm.
As a live music event photographer I get this all the time. Centre point AF and recompose can be made to work well (it's what I use), but to get good at it takes a lot of practice. Other modalities seem to require too much time fiddling with menus when you should be nailing the shot.
I'm sure the focus and recompose method works well for something like a concert, where you're not nearing minimum focus distance with your subject. The example photos posted in this thread show the subject fairly close to the camera, especially for 77mm. That complicates things. It's near impossible to get the subject in focus using focus and recompose, a wide aperture, and having the subject close to minimum focus distance.

Also, I'm not sure what cameras others are using, but I don't use the menu to switch focus points. In fact, my eyes don't even leave the viewfinder as I quickly use the four-way buttons to switch between AF points.
04-30-2013, 09:02 PM   #38
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QuoteOriginally posted by JimJohnson Quote
Here is a picture of what happens when you use the center focus with a shallow depth of field, lock focus, then recompose.
The lines from the focal plane are all the same length. The break in the line represents the current depth of field. I have extended the depth of field from the original center focus, where presumably the subject is placed. When recomposing, the subject distance to the focal plane shifts, but the depth of field does not.
You can always take the the parallel step to the side instead of turning.

04-30-2013, 10:12 PM   #39
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Hi

A repeat of a "tongue firmly in cheek" one liner I posted previously:

One photo out of focus is a mistake, ten is an experiment, one hundred are a style

Greetings
05-01-2013, 06:12 AM   #40
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QuoteOriginally posted by SashasMom Quote
Despite getting lots of shots out of focus I did get some nice ones in focus. I love this lens. (taken with FA 77mm 1.8 limited)
Note: color looks a bit off here, but on my monitor its perfect.
That's such a fabulous shot!
05-01-2013, 06:30 AM   #41
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QuoteOriginally posted by SashasMom Quote
color looks a bit off here, but on my monitor its perfect.
Two things... Most computer monitors are not correctly calibrated. The factory calibration for most is set to make primary color business graphics pop under typical store fluorescent lighting. And the thing is, our brains will do the equivalent of an automatic white balance, so even if you use one of the software-only calibration tools, it probably still is not correct. If you are serious about digital photography, buy or borrow a hardware based calibration tool. Your monitor may not look correct initially - especially in certain room lighting, but typically your brain will do its AWB thing in a few days.

Web sites use the sRGB color scheme. Unless you use the same scheme when displaying the original on your monitor, there will often be some color shift following upload.
05-01-2013, 06:32 AM   #42
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QuoteOriginally posted by VisualDarkness Quote
You can always take the the parallel step to the side instead of turning.
Absolutely true. How many people do this when recomposing?
05-01-2013, 06:34 AM   #43
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The one thing that I think I deal with quite a bit is that the center point is a lot bigger than the edge points. For that reason, it is much more likely to grab onto some contrasty thing that is not quite in the center of an image. I feel like the edge focus points are smaller and therefore less prone to that (as well as probably being a little less likely to lock focus as well).
05-01-2013, 06:46 AM   #44
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QuoteOriginally posted by SashasMom Quote
Note: color looks a bit off here, but on my monitor its perfect.
You can try fixing that by setting the camera and raw editor to use sRGB colour space.
05-01-2013, 09:40 AM   #45
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QuoteOriginally posted by Na Horuk Quote
You can try fixing that by setting the camera and raw editor to use sRGB colour space.
I do have the camera set to sRGB and I use lighroom for editing. I also do calibrate my monitor. So still unsure why color looks different on this site. Maybe someone can enlighten me.
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