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Old Jun 8, 2005, 5:21 PM   #11
NHL
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eric s

This is not the only f/6.3 lens - The 18-200 f/3.5-6.3 behave the same way:

"NHL,

I did a quick check. The camera is set to 1/3 increments. I can select 6.3 in the A/V mode. I'm using it out tomorrow. I'll have my other lenses as backup and for comparison purposes.

Thanks,

Bill
"
http://www.stevesforums.com/forums/v...37&forum_id=65



Also 'fooling' the camera into f/2.8 is not enough for the high-precision AF sensor to work with - The defocus info come from the larger effective lens opening -> "This is because the defocusing shift on the sensors is greater for the f/2.8 light... When the picture is taken, faster f-stop settings also produce more marked defocusing..." i.e. the aperture is a ratio:
http://konicaminolta.com/products/co...x7/ope01b.html
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Old Jun 9, 2005, 2:20 PM   #12
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NHL, I don't believe you refuted my statements.

If you follow the letter of the Canon law, if you have a lens who's max aperture is f6.3, by spec the non-pro bodies shouldn't AF.

But the 50-500 obviously does AF. So to me there are two possabilities:

The lens lies to the camera and reports f5.6 as the max aperture. To my mind, this is a perfectly valid option. It doesn't matter if it is f6.3 for the picture because TTL metering solves that problem.

The camera will really still work at a max aperture of f6.3 and Canon's "law" isn't really a law. It really should say "an aperture less than f8."

I believe the EXIF data reports the max and used aperture (but I could be remembering wrong.) One way to tell might be to look at the EXIF Data for a picture with the 50-500 @500 and see what that field says.

The existance of the 18-200 f/3.5-6.3 doesn't prove anything. It could easily do the same thing (report f5.6.) I don't believe you rounding down idea holds water because then some cameras (the 20D's set to 1/3 stop increments) wouldn't AF because they'd properly report f6.3, but I've never heard anyone saying that it didn't AF... I bet I would have by now. All 3 of my 20D (I've gone through a few replacements) all were set to 1/3 stop increments by default.

I don't see how your last point really matters. Yes, even if the lens lied and reported f2.8 instead of f5.6, it wouldn't work with the high precision AF points because there are laws of physics/optics that produce differences at f2.8 then at f6.3. Having the lens report the wrong value won't just "make it so." And I never said it would. But the difference bewteen f6.3 and f5.6 is so small that the difference in AF quality is probably not that noticable except when AF is already problematic (low contrast/low light.)

Eric
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Old Jun 12, 2005, 10:29 PM   #13
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I have been using the Bigma for well over one year now with both a 10d and 20d. I would not hestitate to recommend this lens at all for outdoor sports and wildlife. I have shot thousands of soccer pictures using the Bigma and monopod. There is no other lens as versatile for shooting large field games without moving up and down the field. Occasionally on a very cloudy day I may have to go to iso 800, but with the 20d that is not really a problem. I have used the lens handheld to take pictures of flying eagles, but have to admit that is a real challenge. I always try to use a tripod or monopod whenever possible. I'm not sure about the specifics of "fooling" the camera or not, but I have absolutely no focusing issues with this lens at 500mm. All of the soccer pictures and eagle shots on my web site were taken with a Bigma.

www.chrismer.net
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Old Jun 13, 2005, 7:51 PM   #14
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Untill just recently it was hands down the best way to get to 500mm. It is a no brainer unless you want to spend more or if you like white and want to cash in your life insurance. I have two years of images I wouldn't have if I didn't have this lens in my bag. Yeahn its heavy and its slow but it is the one to own at that price point. IT works!
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Old Jun 13, 2005, 8:46 PM   #15
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Tomsch wrote:
Quote:
Untill just recently it was hands down the best way to get to 500mm.
OK. I'll bite. What's the best way to get 500mm now?
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Old Jun 14, 2005, 12:33 AM   #16
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Tomsch, nice kitty.

Actually there are two really good reasons to get the really expensive Canon 500mm.
1 - You want the extra stop of light. More than doubling your shutter speed means you can get shots that you might not get otherwise.

2 - It is optically almost exactly as good with a 1.4TC as without. Hard to believe, but its true. And it is only a touch worse with the 2xTC (and it's an amazingly sharp contrasy lens, so "a touch worse" is still a great picture.)

But for many, many people it isn't worth the money or the weight. And it isn't a zoom, which doesn't fit every one.

What do you consider a better way to get 500mm? The 100-300 f2.8 + a tc? that gets you to 420mm I guess. I don't believe it works well with a 2xTC, but that is just a guess not experience talking.

Eric
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Old Jun 14, 2005, 8:36 AM   #17
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When I said untill recently I was refering to Tamrons 200-500mm zoom which is lighter than the sigma and a hundred bucks cheaper.

Eric, please don't try to bait me or put words in my mouth.I said the Sigma 50-500 was the best way to get to 500 at that price point! I also stipified that it was the case untill recently. The Tamron is lighter,cheaper and as such is now another choice at the same price range. Do I think the Sigma 50-500 is the answer to everyones quest, absolutely not! Ninety percent of the time I use that lens it is set at 500mm. The lower end of the zoom is a joke. Why would I use an F4 50mm lens that weighs four pounds when I have a fifty dollar Canon lens that will out perform it by a stop and a half? You go to some length to tout the value of the EF500mm, you won't find an arguement here. We can agree that it is unmatched in all respects except for the price which puts it out of reach for most hobby shootists. If it is a hobby then chances are you don't have five grand in your whole kit! You are talking about spending that on one focal length.

So if you view my pics on this site just know that they are not going to be the quality of Eric's created with his EF 600 L IS. My shots are to show what I've seen afield but at a lesser degree of quality and at a enormous savings. I refuse to carry a lens afield that is worth more than my old pick/up truck.

500mm is 500mm there are just several ways to look at it!


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Old Jun 14, 2005, 9:21 AM   #18
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Tomsch

In your opinion do you think the ultrasonic AF worth the difference in price between the Tamron? IMO Sigma is playing this game just like Canon... :-)

As to the weight I found it quite funny when folks complain of how heavy the Sigma is @ 58.2 oz, but have no problem with the 70-200 f/2.8 IS USM @ 55.38 oz with less than 1/2 the reach
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Old Jun 14, 2005, 1:12 PM   #19
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I didn't know that Tamron came out with that lens. Good, competition in that price range and zoom range is a good thing. (I guess this is NHL's point) I didn't think that Tamron had developed as good AF technology (i.e. it isn't in any of their lenses, not just that one)... but still, any competition (assuming it's similar in quality... exact isn't required) is better than none.

Quote:
Originally Posted by Tomsch
It is a no brainer unless you want to spend more or if you like white and want to cash in your life insurance.
I don't think I was putting words in your mouth, but then again you might not have meant what you said. I view this statment as implying that there was no other reason to get the big white lens. I was just saying that there are other reasons. I still feel the 500&600mm are over priced, but they are also amazing lenses. And I only plan on getting rid of mine when it's too heavy to use any more (and then I'll probably get the 500.)

But it certainly is not really fair to compare the two (500mm & the 50-500mm.) If the 500mm wasn't a lot better, no one would buy it and it would no longer be sold.

Actually, I feel there is a reason to have a zoom on that lens. Maybe not that much, but it can be very helpful when finding subjects. Zoom out a bit, find it, zoom in. I'm naturally good at finding things in the camera (maybe it's from binoc practice?) so it isn't as bad for me with the 600mm as I expected. But it does cost me shots some time when I can't find that small flighty bird... a zoom would help that a lot.

It often scares me that I carry more than the value of my car. I know that feeling very well.

Eric
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Old Jun 14, 2005, 4:45 PM   #20
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How can I set my 350D for 1/3 increments?
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