Am I losing IQ
- Thread starter chauncey
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You can compare that combination to other lenses on the digital picture
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=739&Camera=453&Sample=0&FLI=2&API=2&LensComp=748&CameraComp=0&FLIComp=0&APIComp=0
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=739&Camera=453&Sample=0&FLI=2&API=2&LensComp=748&CameraComp=0&FLIComp=0&APIComp=0
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Just out of curiosity:
Would an 400 L 2.8 with a 1.4 III do better?
The original poster did not mention which generation his 300 2.8 is.
My 400mm is first generation so I do not dare to compare it but in general it would be nice to know.
Would an 400 L 2.8 with a 1.4 III do better?
The original poster did not mention which generation his 300 2.8 is.
My 400mm is first generation so I do not dare to compare it but in general it would be nice to know.
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L
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Kristofgss said:
You can, and that's my 'case 1' above, where the images weren't cropped but rather the distance is doubled when the 2x is used**. The TDP comparison is useful – it addresses issues such as comparing 300mm+2x vs 400mm+1.4x vs. native 600mm, comparing MkII vs. MkIII TCs, etc.
But the tool also gives the impression that adding a TC always reduces IQ, and that's not the case. In fact, I would argue an appropriately-used TC often doesn't reduce IQ – in real world use, if I could just walk closer and cut the distance to my subject in half, I wouldn't use the 2x TC...I'd just walk closer. The TC is used when I can't walk closer, and would need to crop deeply instead, and in that case the IQ is better with the TC.
**Technically, Byran shoots the native 300mm and the 300+2x at the same distance, but for the latter he uses a test chart that's 1/4 the size (his testing space doesn't allow enough space to frame the large chart at 600mm FL). Because of the chart design (he uses Applied Imaging QA-77 charts, based on the ISO12233 standard), the resolution scales exactly across all four chart sizes when you fill the frame with the chart.
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The use of a teleconverter ALWAYS degrades the image.
That said, there are a couple of other questions you have to ask....
Is the degradation of the image enough so that there is a noticeable difference? This depends a lot on the camera and the lens. A camera with a finer pixel pitch will be more likely to show a noticeable difference, hence the rule of thumb that crop cameras, with their smaller pixels, don't work as well with teleconverters as do FF cameras..... A high quality, very sharp lens (can you say big white.....) after the degradation of the image by the teleconverter is still a fairly sharp lens, while kit lenses and many zoom lenses (there are some high quality exceptions) are already showing visible drop in IQ before the teleconverter is added and afterwards it is noticeably worse.... this gives us a second rule of thumb, which is that teleconverters work best on "L" lenses.
When using a 2X teleconverter on a distant object, you will get 4 times as many pixels on the target, but they are lower quality pixels. The question becomes, do these greater number of lower quality pixels resolve more detail than the fewer number of higher quality pixels from without the teleconverter. The odds are that if you are shooting a FF body and "L" lenses, that they do, and if you are shooting a crop camera with a non-L lens, that they do not... anything else and you have to experiment.....
For example, I have a 5D2 and a 70-200 lens. Put a 1.4X teleconverter on it and it resolves more distant detail. Put a 2X teleconverter on it and it resolves even more. Now I pick up a 7D2, and try again.... With the 1.4X teleconverter on, it resolves more detail.... but with the 2X teleconverter the resolving power drops!
That said, there are a couple of other questions you have to ask....
Is the degradation of the image enough so that there is a noticeable difference? This depends a lot on the camera and the lens. A camera with a finer pixel pitch will be more likely to show a noticeable difference, hence the rule of thumb that crop cameras, with their smaller pixels, don't work as well with teleconverters as do FF cameras..... A high quality, very sharp lens (can you say big white.....) after the degradation of the image by the teleconverter is still a fairly sharp lens, while kit lenses and many zoom lenses (there are some high quality exceptions) are already showing visible drop in IQ before the teleconverter is added and afterwards it is noticeably worse.... this gives us a second rule of thumb, which is that teleconverters work best on "L" lenses.
When using a 2X teleconverter on a distant object, you will get 4 times as many pixels on the target, but they are lower quality pixels. The question becomes, do these greater number of lower quality pixels resolve more detail than the fewer number of higher quality pixels from without the teleconverter. The odds are that if you are shooting a FF body and "L" lenses, that they do, and if you are shooting a crop camera with a non-L lens, that they do not... anything else and you have to experiment.....
For example, I have a 5D2 and a 70-200 lens. Put a 1.4X teleconverter on it and it resolves more distant detail. Put a 2X teleconverter on it and it resolves even more. Now I pick up a 7D2, and try again.... With the 1.4X teleconverter on, it resolves more detail.... but with the 2X teleconverter the resolving power drops!
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Correct! You can have cases where in theory the image is degraded, but the camera is not able to notice those changes.neuroanatomist said:Don Haines said:
So NOT always, at least when considering the final output (which is what really matters).
Teleconverters are one of those things where there is no set answer as it depends on so many variables....
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