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 p.11 #15 · IS: Canon must show its colours | |
jvarszegi wrote:
No, sorry. Lens-based IS is not better than in-body IS, just different.
That sir, is absolutely false.
No.
The two technologies are different.. and they simply are not equal. A 70-200IS will always be better at 3/focal length @ 200mm than a 70-200 nonIS on a sensor IS based body.
Advantages of lens based IS:
Again, I did not say lens-based IS had no advantages. In-body IS also has HUGE advantages. What I said was that it is comparing apples to oranges to say one is better than the other. Read better.
Oranges and Apples are not equal.... Oranges are pretty crappy in apple pie just as sensor based IS is inferior in about 8 situations I have pointed out.
1) stabilization of image in the viewfinder
A complete non-issue at the focal lengths where in-body IS works well.
If it's a visible difference it cannot possibly be a non-issue. Interesting that you admit freely that there are focal lengths where in-body IS is clearly inferior. Do you believe a focal length exists where sensor based IS is superior? If no such focal length exists then you have just proven that lens based IS is in fact BETTER overall.
2) New systems effective for 4 stops (both nikon and Canon) and full range of focal lengths.
On a limited selection of lenses. Does not mean in-body IS is not effective. Here, in-body IS has an advantage on most of the lenses in the Canon lineup.
Do you believe the first implementation of in-body IS will have the same success as a 3rd or 4th generation lens based IS?
3) Does not create distortion blur in non-rectilinear lenses.
I think this is FUD. I don't see people complaining of distortion blur in non-rectilinear lenses on the Sony system etc.. Prove the effect of this, and start by saying better what you're talking about. Can you show an example of the two side-by-side to show the harmful difference? Also, what does it matter? In-lens IS is not available on the lenses I'd use with in-body IS.
You don't see it because people are justifying their purchase by pretending it doesn't exist.
If I had the spare money and tools I would be glad to create a shift mount for any lens you would like to see me use to demonstrate this simple optical effect. Until then, please go pick up a large magnifying glass and look through it. Now hold the glass still and move your head 1 inch to the left. If you cannot see how this distortion blurs while you move your head you won't understand the test results either.
Simply put, if the lens is not perfectly rectilinear, you cannot move the sensor in a rectilinear fashion and expect it to catch the same light it would have in it's previous position.
4) Does not create perspective blur in perfectly rectilinear wide angle lenses
More empty talk
I assume you believe that shift lenses are as fictional as the easter bunny then. If you realize they exist, pick up a nice 24mm ts-e, mount your camera on a very heavy tripod pointed at a tall building and then shift the lens 1mm downward during a long exposure.
5) Works with full frame
So can in-body IS. All of the arguments against are wrong that I've seen so far. Even L lenses with baffles have larger-than-sensor coverage already-- and baffles can be removed. For all other lenses, the supposed vignetting issue is absolutely negligible.
With objections against, I feel that you should sustain the burden of proof. Show that you're right instead of just repeating empty words from the opinion of others.
Apparently you haven't seen the mass of threads complaining about light falloff on the 16-35 or 17-40. Those threads are with the sensor in the CENTER of the image... imagine what it would look like when you move the sensor outside of the center.
6) Works with ef-s and "digital only" lenses
Ditto.
Yeah, ditto my previous response too.
7) More effective at long focal lengths.
Go read my post. This does not make in-lens IS better. For me, in-body IS would be better, because I would have a stabilized 85L. This argument was thought of by a wishful-thinking sports or wildlife shooter, interested in feeling good about the money they've dropped on their IS lenses. It was certainly not concocted by a people shooter.
Wow, I did read your post. I read the post I'm responding to where, when you tried to refute #1, you admitted that it sensor IS is not effective at all focal lengths. I can only assume you meant long focal lengths. Should Canon choose to produce an 85 L IS it will be superior to using an 85L on a body with sensor IS.
By the way, I have found that people move and that during 1/30th or 1/15th exposures the camera tends to catch that as what I call "motion blur". Do you really want a few stops on your 85mm when shooting people?
8) Designed to perfectly match the specific lens being used.
No IS in the majority of lenses in use today. Again, the fact that in-lens IS is superior on a few lenses does not mean in-lens IS, as a generic feature set, is superior. Read my post. It's simple.
Your'e right again... lens based IS is only superior everywhere it's implemented.
9) Does not move the sensor out of the "sweet spot" of the sensor for a percentage of the exposure creating a blur between max sharpness and something worse
I guess I cannot match your logical prowess by entering into a debate about moving the sensor out of the sweet spot of the sensor. Instead, I'd like you to show some sort of evidence that you're not just blowing hot gas.
I don't think it's hard to find charts on the internet that show how sharpness falls off to the outside of the image circle. If you believe I'm blowing hot gas, please search for "soft corners" on this forum. I believe you will find plenty of examples... probably some with 100% crops from the center and corners.
If you are going to state that Lens IS is equal to sensor IS please back up the statement by creating a list of advantages for Sensor IS that is equal to the one I have just given you.
Availability
Cost
You obviously don't shoot people in low light.
I believe that availability would fall in the corner of lens IS (unless you shoot pentax or sony.
Cost? Yes it's true... they tend to charge less for the inferior image quality provided.
And again, I don't have great hopes of shooting people at 1/15th or 1/30th, I don't care what lens I'm using.
As a suggestion, do not include cost in your list. Currently there is no lens-IS based system that can equal the image quality of a XTi + 17-55IS and 70-200 f/4IS @ 3/focal length at ANY PRICE.
Your argument is specious. A body-stabilized 85L, for instance, would below the 17-55 IS away in its specialized area.
And again, 85L IS would blow away a body stabilized 85L. If you want 1 more reason that Canon should not produce body with sensor based IS it is this: If they do, the likelyhood of Canon producing more great lenses with IS would be greatly decreased. With all of the cheap people out there trying to take the cheap way out via sensor baed IS, they won't be able to recoup development costs selling to the few that are willing to pay more for the higher quality.
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You made yourself look silly.
. 
? Why didn't the 16-35L II