Teleconverter image quality


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smtan24

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#1
I'm told that image quality degrades wiith use of a teleconverter. But nobody has told me how bad it is. Any one got pictures using a teleconverter which we can use to compare how bad the image is?
 

raptor84

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#2
Basiclaly it would make it softer and have slighly less contrast/saturation and higher CA... in general if you stick to orinal stuff it degrades less...
 

smtan24

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#3
Would a well made teleconverter reduce this problem? Are the image produce by the teleconverter usable if resized.
 

JLLJ

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#4
smtan24 said:
I'm told that image quality degrades wiith use of a teleconverter. But nobody has told me how bad it is. Any one got pictures using a teleconverter which we can use to compare how bad the image is?
Quality is definitely degraded. A good quality converter will definitely reduce the problem.
For compact add on, do take note of the distortion towards the edge of the image.
For Dslr, x1.4 tele gives very acceptable quality that you might not see much diff from without. higher magnification than that will produce more obvious degradation to the image. Again, it will depends on how big you want to blow up your photo.
It is also affected by how good your original lens (esp zoom lens) is bec tele will also magnify the flaws/inperfection of your lens (i.e. distortion).
Also note that tele will reduce your effective aperture size and hence the lens may have difficulty to focus in low light condition and will experience longer exposure time.
 

surge

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#5
teleconvertor works by magnifying the center portion of the image. thus, to start w, the original lens must be very sharp inhte center. cos any flaws in the original image will be magnified also thru the convertor.

secondly, there are different grades of convertors also. some simply 'magnify the center portion'. thus quality not that good. some are made after consideration of their own brand of long lens and these convertors are suppose to be pair w these lens to produce the desire results. ( optically matched closer).

so to start w make sure you have a sharp lens wide open(since convertor will cause you to lose one stop) to start w.

if you use say a70-300/5.6 at 300 end , close 1-stop cos its soft wideopen, plus the 1-stop lost already f11 when you shoot.

consider a 450/11, you wil need a rather strong light to get at least 1/500 shutter before motion blur comes in
 

smallaperture

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#6
And that makes me think of this question:
A Shoot with a 80-200F2.8 at 200mm and then, crop to get the equivalent of 400mm.
B Shoot with a 2x TC added.

Compare the result. Assuming you shoot both at say F8. Which is better? Theoretically better? In practice, shooting handheld? A significant difference?

Here is a logical answer without even trying it out - B has got to be better. Or else why border to produce TC at all, and why spend money to buy and use it after all. Moreover, it is more difficult to shoot with TC, lose a stop or two, heavier and cost money!
 

surge

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#7
smallaperture said:
And that makes me think of this question:
A Shoot with a 80-200F2.8 at 200mm and then, crop to get the equivalent of 400mm.
B Shoot with a 2x TC added.

Compare the result. Assuming you shoot both at say F8. Which is better? Theoretically better? In practice, shooting handheld? A significant difference?

Here is a logical answer without even trying it out - B has got to be better. Or else why border to produce TC at all, and why spend money to buy and use it after all. Moreover, it is more difficult to shoot with TC, lose a stop or two, heavier and cost money!
think is when you do cropping you get lesser pixel. its like digital zooming in compact cameras
 

#8
smallaperture said:
Here is a logical answer without even trying it out - B has got to be better. Or else why border to produce TC at all, and why spend money to buy and use it after all. Moreover, it is more difficult to shoot with TC, lose a stop or two, heavier and cost money!
Because you can then have 200mm X 1.7 for example which is 340mm and then you can crop and get 500mm at a decent quality, that is 100mm futher!

That is a great advantage of a TC.
 

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