Comments on new review of 600mm II just posted

Bryan, I always appreciate your reviews and optical comparison tools. Thank you for the review of the 600mm II. I did have one comment, that I disagree it might obsolete the 800mm. If you only ever need 800mm of focal length, and no more, then I will accept your statement that the 600mm II with a 1.4x III is as sharp as the 800mm, but cheaper and lighter, and gives you a 600mm f4 as well. But for avian and wildlife photography, there is no such thing as too much focal length. I sometimes use my 800mm with a 1.4x II to give 1120mm, even with a 1.6 crop camera. Some softening due to diffraction is clearly visible, but I can achieve more resolution with this combination than by using 800mm and cropping. My point is that the 800mm + 1.4x combination has better image quality than a 600mm + 2x, hence the 800mm still plays an important role.

Of course, the 800mm can also be used with a 2x extender. But with an 18 Mpix 1.6 crop camera, the image is so soft that it gains little resolution compared to just cropping. Therefore I don't bother carrying a 2x extender anymore. But when I upgrade to a 5D III, I can probably get useful images from an 800mm + 2x combination, because the diffraction limit is higher due to the larger pixels. Again, then, the 800mm still retains an important advantage of more focal length over a 600mm + 2x.

My wildlife kit has three lenses: the 300mm f4, the 500mm f4 I and the 800mm. Each lens increases my focal length by 1.6x which I find about right. Interestingly, although your tests show that the 500mm II is sharper than the 500mm I, I don't feel any need to upgrade my 500mm I, because I never use it with a 1.4x extender. I use my 800mm instead. Therefore my 800mm allows me to get away with an older and cheaper 500mm than I might otherwise desire.

Any other comments from anyone on the new review of the 600mm II?

The review is very good, and I appreciate the time that Bryan put in to the review.

@ Scully I think if the 800 v 600 is based only on the extenders you could make the same argument that the 500mm would do as well, it looks very good at 1000mm vs the 800 at 1120. http://www.the-digital-picture.com/R...mp=3&APIComp=1

From what I have seen and read so far, I was thinking the comparison might be made that a 600mm might be the better choice over a 800mm for the reasons Bryan expressed. In fact it was one of the questions I was curious about, how the 600mm would stack up with the extender against the 800mm. The charts at 840mm do look very good.

Finaly there is someone with the 800mm on this forum!:D

I am sort of in between Bryan and you about the 800mm being obsolete, if you use 800mm more than 1200mm than I see the advantages with the 600mm II. But in your case (and my case) I would probably choose the 800mm over all because I would use 800mm+ range more often. So the way I see it there is a place for both of these lenses but the 600mm is more versatile.

But it is sure is temting to have a 600mm f/4 and still have a very good, if not equivalent IQ in the reall world, and a still decent 1200mm. And because of that I still havent made up my mind completely on which one I would pick up once I have saved up enough money for either.

I have not shot alot with 600mm on a FF, I have shot some with film on my 600mm f/6.3 but not enough to know exactly how much I would use it, I think I would use most in setup blind situations were the extra IQ would be more prevalent than in the field were many shots will probably be above ISO 800 or have VERY slight motion blure in fast action.

But really the deal breaker for me would be AF performance with extenders. If it's like the older extenders were AF is reduced by 50% with the 1.4x and 100% with the 2x that would push me over the edge for the 800mm.

BTW, I plan to upgrade to FF when I jump on either lens. Probably the 5D III or if I have saved enough the 1D X.

Cheers,
John.

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Originally Posted by FastGass

But really the deal breaker for me would be AF performance with extenders. If it's like the older extenders were AF is reduced by 50% with the 1.4x and 100% with the 2x that would push me over the edge for the 800mm.

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Unless you have a 1 series body you will not be able to focus either of those lenses in Auto, unless you tape the sensors.

The OP mentioned he used a crop body, for a crop body I am more impressed with the 600mm with the 2x ISO charts than the 800mm with the 1.4x. The reason is that the crop body will not even be using the corners. The mid frame of the 600mm than the 800mm mid frame, and the 800mm in the center has a very slight edge. The 800mm wins in the corners, but unless you are full frame the corners do not matter. In actual use I don't think you will notice much difference between these two combinations unless you are full frame.http://www.the-digital-picture.com/R...mp=3&APIComp=1

Really I am not that impressed on any of the lengths ISO charts longer than the 500mm with the 2x, I think at 1200 and 1120 the 600mm and 800mm are loosing to much. http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=745&Camera=453&Sample=0&FLI=2&API= 0&LensComp=459&CameraComp=453&SampleComp=0&FLIComp =3&APIComp=1

Edit; One other point, I don't think the 800mm ISO is really beating the 600mm with the 1.4x;http://www.the-digital-picture.com/R...mp=1&APIComp=1

I was thinking more in terms of the 1.4x, taping the pins would be my only option with the 1Dx but still an option with a 1D IV which is not completely out of the equation. If I lost a significant amount of AF speed at 840mm were I will be mostly shooting at that would be a deal breaker for me.

You are right, from the ISO charts the 800mm seems to to be only SLIGHTLY sharper in the corner and actually are slightly worse in the mid frame and about the same in the center. I think the CA is the biggest differentiator, which DxO handles very well even when it's not profiled. To me the only reall IQ advantage is at 1200ish range were the 800mm handles the corners better, but I don't really have anything that far in the corners very often. And even then it's not a huge difference.

John.

So Rick, have you made up your mind yet? Is a 500 mm II ordered? Just livin' vicariously..... :)

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Originally Posted by Kayaker72

So Rick, have you made up your mind yet? Is a 500 mm II ordered? Just livin' vicariously..... :)

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I need to go head and put my 500 mm up for sale to help fund it. Looking back I would say 70-80 percent of my shots were hand held. A fair percentage of those shots were fast captures where you had to act fast to get the shots. A fair amount if shots were lost because of not being in a position to move the big heavy lens fast enough. Taking all that in to account I think I could improve my pictures more with the lighter shorter 500mm lens. I of course like to have the longer lens but I don't think it would be as versatile for how I shoot.

Ideally though, if the 200-400mm really existed, and it's IQ was acceptable, perhaps the 200-400mm plus the 600mm would be the better move to replace my 300mm plus 500mm. But that option doesn't exist yet.

So I will say for sure, when I hit the buy button my mind will be made up. Probably not 100% for sure one second sooner.