Opticallimits

Full Version: Sony A55 - fps compensating AF speed
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Pages: 1 2

Guest

(I know the community here tends to dislike my pictures, but this time I need some to demonstrate the case.)



I claim that in many practical cases high continuous-shooting frame rate of the Sony A55 can compensate for the presumed AF-speed deficiency.



I don't really care whether the camera fitted with 50mm f/1.4 in someone's hands can track an approaching train.

What I already know, is that in my hands, when fitted with either 16-80 f/3.5-4.5 or 70-210 f/4, it's unable to track my dog running towards me.



So, my solution is to preset the focus for the desired subject size, set the 6 fps or 10 fps mode, and keep the shutter pressed for approximately a second at the right moment.

After several rounds I'm rewarded with 1-2 usable pictures.



By the way, the dog's picture here is taken with an MF lens - Jupiter 37 - 135mm f/3.5 - made in USSR in early 80s. It has enormous number of aperture blades, and thus greatly outperforms the 70-210 set at 135mm in defocusing the background trees.



The flower-and-bug picture was taken with the 16-80 and 10 fps. The swinging of my head with the attached camera did the focus-guess job.
[quote name='olegk' timestamp='1305650577' post='8422']

(I know the community here tends to dislike my pictures, but this time I need some to demonstrate the case.)



I claim that in many practical cases high continuous-shooting frame rate of the Sony A55 can compensate for the presumed AF-speed deficiency.



I don't really care whether the camera fitted with 50mm f/1.4 in someone's hands can track an approaching train.

What I already know, is that in my hands, when fitted with either 16-80 f/3.5-4.5 or 70-210 f/4, it's unable to track my dog running towards me.



So, my solution is to preset the focus for the desired subject size, set the 6 fps or 10 fps mode, and keep the shutter pressed for approximately a second at the right moment.

After several rounds I'm rewarded with 1-2 usable pictures.



By the way, the dog's picture here is taken with an MF lens - Jupiter 37 - 135mm f/3.5 - made in USSR in early 80s. It has enormous number of aperture blades, and thus greatly outperforms the 70-210 set at 135mm in defocusing the background trees.



The flower-and-bug picture was taken with the 16-80 and 10 fps. The swinging of my head with the attached camera did the focus-guess job.

[/quote]

I would not mind what some say about your pictures, Oleg. there are some that at times make the most ignorant comments to my images too, and such comments have no value.



What a funny cute dog you have! Seems very playful, huh?



I do not think that your solution, to counter the not so good AF tracking speed, is to just fire away machine gun style.... Not only does it give you vast amounts of unnecessary data, but it also wears your shutter life time down drastically.... If AF tracking speed is what you desire, maybe a different brand body with fast AF-ing lens might be a nice addition.



I myself have not yet had the need for fast AF tracking, but some tests I ran to illustrate the silliness of some claims regarding the A55v did show that even my 450D can do an adequate job in certain circumstances, tracking "fast" moving subject, with my 70-200mm f4 L USM.



Your 70-210 is the well-liked Minolta f4 "beer can", am I right?



The bumble bee is quite nice too.



I don't think the number of aperture blades will defocus more, but it might make "highlights" more smooth. How many aperture blades does it have?

The lens with the highest number of aperture blades that i have is the Nikkor-Micro_Ultra 55mm f2, it has 12 aperture blades!

Guest

Plu IR tested A55 and 7D side by side found AF tracking to be comparable <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='Smile' /> That says it all. The Canon counterpart in this price range (550D) does whooping 3.5 fps with teeny tiny buffer <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='Smile' />



Even mirrorless cameras do better than that.



As for AF tracking, get SSM lens and it works even in video mode that even overpriced 7D can't



http://www.youtube.com/watch?v=ym7OkYpP_...ideo_title



http://www.youtube.com/watch?v=kHPaVD0pHpQ
[quote name='oneguy' timestamp='1305652176' post='8429']

Plu IR tested A55 and 7D side by side found AF tracking to be comparable <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='Smile' /> That says it all. The Canon counterpart in this price range (550D) does whooping 3.5 fps with teeny tiny buffer <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='Smile' />



Even mirrorless cameras do better than that.

[/quote]

You can repeat the same stupid line over and over again... does not make it real.



There never has been a 7D and A55v comparison, there have never been published results of such a comparison either.



What has been there is a wonky claim by a commercial website who, to please Sony in exchange to being the only site to publish a "review" at the day of press introduction of the camera, wrote a favorable "review".



Without any actual comparison, and with a silly, bogus claim.



Anyway, what on earth has your post to do with Oleg's post?

Guest

[quote name='Brightcolours' timestamp='1305652628' post='8430']

You can repeat the same stupid line over and over again... does not make it real.

[/quote]



You can repeatedly deny it, but they said they did and I will take their words over some fanboy who hasn't even touched the camera.

Quote:We shot side by side with the Sony A55 and a Canon 7D, and felt that the A55's AF performance here was pretty similar to that of the much more expensive Canon.

Guest

[quote name='Brightcolours' timestamp='1305652628' post='8430']

Anyway, what on earth has your post to do with Oleg's post?

[/quote]



What does your post has to do with his post about your 450D? This isn't Canon thread. Why are you posting everywhere with your Canon stuff?
[quote name='oneguy' timestamp='1305652962' post='8433']

What does your post has to do with his post about your 450D? This isn't Canon thread. Why are you posting everywhere with your Canon stuff?

[/quote]

If you read my post like a NORMAL person, you would understand its context.

Guest

[quote name='Brightcolours' timestamp='1305653821' post='8435']

If you read my post like a NORMAL person, you would understand its context.

[/quote]



Yes, I did read the post. The post was about A55, a camera that you don't own, and you had no business complaining about AF of a camera that you haven't even touched, and plugin your Canon in unrelated thread. What's your problem? Why are you everywhere on this board with your canon nonsense? Are you paid by Canon shill?

Guest

Well, I really didn't intend to open another camera comparison thread; it was more about a technique.



So, keeping the emotions away, I want to say that better gear (no matter what brand) will not help to focus in many real-life scenarios.

Comparing cars to dogs: cars have larger sizes and more predictable routes, but to me dogs are practical scenario, while cars are not <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='Smile' />. I tried hard, and I know I cannot keep a running dog under an AF sensor, especially on an EVF camera. This means it doesn't really matter how good the AF system is, with me as the user it will miss the shot.

People naturally occupy slots in-between dogs and cars, so it depends. May I suggest to redo the test with the nice young woman, while asking her to do unpredictable steps to the sides <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='Smile' />?



Answering the questions:

- The 70-210 lens is Minolta beercan.

- I frankly gave up counting aperture blades on the Jupiter lens there are too many.

- The Jupiter lens excels in the shapes of defocused features (tree branches this time); the beercan renders them pretty ugly; even though it's khown for what is called bokeh to be pretty good.
[quote name='olegk' timestamp='1305656051' post='8446']



Answering the questions:

- The 70-210 lens is Minolta beercan.

- I frankly gave up counting aperture blades on the Jupiter lens there are too many.

- The Jupiter lens excels in the shapes of defocused features (tree branches this time); the beercan renders them pretty ugly; even though it's khown for what is called bokeh to be pretty good.

[/quote]

- Aha, I don't understand why Sony (or indeed Minolta before) does (did) not upgrade the 70-210 beercan, It should be a lovely lens, and also popular, judging by the success of the Canon 70-200mm f4 L USM and 70-200mm f4 L IS USM.

- Now I am even more curious about number of blades, haha!

- The shapes of the foliage in the dog image indeed are rendered quite pleasingly. Great job for MF!
Pages: 1 2