Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Sony Alpha dSLR / Konica Minolta dSLR, Sony SLT

Reply
 
Thread Tools Search this Thread
Old Nov 14, 2010, 5:48 PM   #61
Member
 
Join Date: Mar 2010
Posts: 39
Default

Jim.

Thanks again. My takeaways for that shoot next time, as if there will be a next time, are:
1. Set autofocus to continuous. Just didn't think hard enough before taking the shot.
2. AF to centre point. Hear you on that although given the width of the subject(s) that may still have result in some loss of sharpness (the lens was a minolta 17 -35)
3. get the shutter speed up to 1/500 th of a second after first opening up the aperture and then using the ISO to control shutter speed.
The lens has a neutral filter, don't think its polarising but will check.

very irritating as we have great light here in australia, and the chilrend make great subjects for a camera when they are in the right mood.
ozboy is offline   Reply With Quote
Old Nov 14, 2010, 6:03 PM   #62
Senior Member
 
frank-in-toronto's Avatar
 
Join Date: Mar 2010
Location: Toronto Canada
Posts: 1,083
Default

In the images posted you have a subject in the middle. but if you had only 2, your center focus point would be background.

i've missed quite a few shots for that reason. next time i'm going to set multi-point focus and see how that tracks. sometimes i just frame wide and keep on one subject planning to crop for better composition later.

and there's something wrong with this statement:"2. AF to centre point. Hear you on that although given the width of the subject(s) that may still have result in some loss of sharpness (the lens was a minolta 17 -35)"

the width has nothing to do with af center or not. you only get one plane in focus. so i'm not sure if you have a misconception or just wrote it a little wrong.

Last edited by frank-in-toronto; Nov 14, 2010 at 6:06 PM.
frank-in-toronto is offline   Reply With Quote
Old Nov 14, 2010, 6:16 PM   #63
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

I've seen some users report getting better results using Wide Area AF. I got used to sticking with Center Point using my 5D so I'd know what I was locking on + it's more sensitive than the others for greater accuracy in low light. Actually, I just set it to Focus Area selection so I can select any AF point I want to, and just use the Center Button when I want to use Center.

The reason I suggested Center Point is so the OP would know what it's focusing on after a half press (making sure one of the subjects is at the center point). When using Continuous AF, the camera is still going to use all AF points (and if you watch the viewfinder carefully, you should see the active point briefly illuminate if another one is used instead of the one you used to lock with initially when the subjects are moving).

But... for a group shot like that, Wide Area could work, too. The only problem with that is if it locks on something other than your intended subject (since the camera is deciding what to lock on versus you deciding what to lock on).
JimC is offline   Reply With Quote
Old Nov 14, 2010, 6:58 PM   #64
Senior Member
 
Join Date: Jan 2010
Location: Western Ma. USA
Posts: 795
Default

there have been some really long posts on this thread so forgive me if i reiterate something that has been said...

using the a55's 10fps mode, the camera picks the exposure, iso, shutter speed, and aperture. (please correct me if i am wrong about that).

The most notable about the camera's self selections is the shutter speed. I do believe that the a55 chooses 1/500th as the fastest shutter speed it will choose. That is NOT really fast enough to capture anything more than a young child's sports shot..

that would be a serious deal breaker for me considering the 10fps would be most likely used during sports (of adults), and 1/500th isnt fast enough, therefore i would end up with lots of photos in focus, but they'd all be blurry due to subject movement. lol.
what a stupid decision by sony.
__________________
ewheeler20 is offline   Reply With Quote
Old Nov 14, 2010, 8:18 PM   #65
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Eric:

That's not what I'm seeing reported by A55 users (fastest shutter speed of 1/500 second). I've been seeing the opposite reported (it tries not to go slower than 1/500 second). ;-)

Yes, the camera doesn't allow you to change anything in 10fps mode. If you want full control, you'd need to stick with 6fps.

But, I've been looking at 10fps sequences at a wide variety of shutter speeds (1/800, 1/1250, etc.). Apparently, it tries to keep the shutter speed as fast as possible, with a goal of trying to keep the shutter speed at 1/500 second or faster from reports I'm seeing.

For example, I just saw a report from an A55 owner testing it indicate that he was getting 1/2000 second at f/4.5 (the max aperture of the 16-80mm lens he had on it when zoomed in) at ISO 100 in bright light pointing it at a brighter house. When he pointed it to a darker area in 10fps drive mode, the camera then increased ISO speed to ISO 1600 and shot at 1/500 second.
JimC is offline   Reply With Quote
Old Nov 14, 2010, 8:33 PM   #66
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

P.S.

1/500 second is actually a pretty good target shutter speed for sports (keep it at 1/500 second or faster), which is the way the 10fps mode appears to be designed from user reports I'm seeing, at least with the production firmware.

Sure, you might see a bit of blur with very rapid hand/ball/foot movement. But, for the most part, 1/500 second minimum is a very good target to insure sharp subjects.

Of course, faster can be better if lighting and lens permits, and that's the way the A55 appears to be designed, using faster shutter speeds than 1/500 second in conditions that allow it (it's Auto ISO tops out at ISO 1600).

Of course, if lighting won't permit 1/500 second at ISO 1600 with the widest aperture your lens supports (for example, trying to use an f/5.6 lens indoors), then you're not going to get shutter speeds that fast with the 10fps drive mode. ;-)
JimC is offline   Reply With Quote
Old Nov 14, 2010, 8:36 PM   #67
Senior Member
 
Join Date: Jan 2010
Location: Western Ma. USA
Posts: 795
Default

so if i am not in a high-light situation (a gym for example), it will probably drop the shutter speed to 1/500, and increase iso and aperture. But in reality, what i'd want to do is keep my shutter speed at 1/2000 or so, and bump up my iso even more in addition to the maximum aperture possible.
__________________
ewheeler20 is offline   Reply With Quote
Old Nov 14, 2010, 8:38 PM   #68
Senior Member
 
Join Date: Jan 2010
Location: Western Ma. USA
Posts: 795
Default

if i were to use the a55, the most likely condition i'd be shooting in was an indoor gym watching college-level volleyball. I'd use the sigma 70-200 f2.8. I am afraid that the auto settings would not be good seeing as it would most likely bump my shutter speed to 1/500, which is def. not enough.
__________________
ewheeler20 is offline   Reply With Quote
Old Nov 14, 2010, 9:04 PM   #69
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

I'm not sure I understand your comments...

For one thing, in typical HS gym lightinng, you'd need to shoot at ISO 3200 and f/2.8 just to get your shutter speeds up to around 1/400 second (which is what a lot of basketball shooters do); or use around f/2 at ISO 1600 to get shutter speeds that fast (if you want a properly exposed image).

So, you'd need a prime lens with f/2 available to get close to 1/500 second in typical gym lighting if you wanted to use the 10fps mode (since the camera's Auto ISO is going to top out at ISO 1600). ;-)

1/2000 second indoors in not realistic, even if you're setting everything yourself. You'd probably need to use ISO 12,800 with a brighter prime to get shutter speeds that fast in a typical High School gym. I think you'll find that shutter speeds of around 1/400 to 1/500 second are typically used for most indoor sports with good results, with some exceptions (gymnastic floor routines with very rapid movement, martial arts if you want to have blur free faster kicks, etc.).

But to keep the main subject sharp for most sports shooting, 1/400 to 1/500 second is adequate. If you can get 1/640 second or so, great (less blur in rapidly moving hand/foot/ball movement). But, 1/2000 is unheard of in most gym lighting (and I've seen reaonably good results from shooters using shutter speeds as slow as 1/250 second when using wider framing (as blur from subject movement is harder to detect when it occurs across a smaller portion of the frame for a given viewing size, as you'd have when your subject makes up a smaller percentage of the frame).

IOW, you really don't need 1/2000 second (and it would be very difficult to achieve indoors anyway, even if you had full control over all settings).
JimC is offline   Reply With Quote
Old Nov 14, 2010, 9:08 PM   #70
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

I was typing when you made your last post... College level, huh? Lighting is probably going to be a bit better than you'd find in typical HS gym lighting. You'd have to try one to see how it behaves in that type of lighting. But, I suspect it's going to stay at 1/500 second to keep ISO speeds lower in brighter gyms (if lighting is good enough for shutter speeds that fast at ISO 1600 for the widest aperture your lens supports). But, that would be pretty bright gym lighting in order to get 1/500 second at f/2.8 and ISO 1600 (about twice as bright as the gyms in my area) if you want a properly exposed image.

If I see further reports (I'm seeing posts around the net from number of users testing them now to figure out the 10fps behavior), I'll post what I find here.

But, if you want full control, you'd need to stick with 6fps.
JimC is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 4:30 PM.