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Need advice...is the "IQ" I get finally normal for the used gear, or should it be better?
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Aug 4, 2022 16:28:15   #
Dan' de Bourgogne
 
Hello, You skilled friends! I got a gift: a téléconverter KENKO "x1,5".
In fact, this "lens" is supposed to add "50%" of the already used FL.
I checked the effect :without Kenko compared with Kenko. No problem: FL seems quite "longer"
1) How do You check if You get "50%" bigger FL...and not 40 or 60?

Adding some "glass" in the optical path of light, I expect the IQ will probably get a bit altered.
I have no idea if the result I got below is "normal"...or rather good...or really bad.

2) In fact, I would like to know if I rather should sell this Kenko and buy a better one.
Psttt....I'm afraid, I'm not very happy using this converter...not so much because the IQ...but much more because the AF is very unefficient!!!

3) Do You know a brand of x1,5 converter letting the initial AF working quite nicely?

Both pictures were shot while the function "image DX x 1,3" was enabled...my aim was to get the subject filling the frame
Both pictures were shot while the function "image ...
(Download)


(Download)

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Aug 4, 2022 16:43:14   #
imagemeister Loc: Stuart, Florida
 
Kenko 1.5X is quite OLD - a holdover from the film era - I tried one on film - very disappointing ! - even when used with a decent lens. Kit lenses especially, do NOT do well with optical extenders - most usually better to optimize your lenses' native IQ and CROP and use pixel enlargement software if needed for larger printing.

Kenko's latest and greatest 1.4X ( $200 +) would be your best optically extending solution.
.

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Aug 4, 2022 16:53:00   #
Alphabravo2020
 
I think it will be hard to compare IQ with those exposure settings.

Shutter speeds of 1/80s and 1/20s are pretty long for an outdoor shot at 200mm. Any movement will blur the shot.

Also I think it unlikely that the best IQ is at F/11. The lens is likely to be sharper at f/8 or even lower.

I would want to be closer to ISO 400 for an outdoor shot. I know my D850 is pretty grainy at 1200. A wider aperture will allow you to lower the ISO and also increase your shutter speed.

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Aug 4, 2022 16:54:27   #
User ID
 
Its typical for generic TCs to vary from their nominal magnification. They are mostly impractical except at the most elite level. Youll get better results by resampling in PP.

Even if you just crop to 1.5X, youll still have half your MP which is more than enough for any purpose.

If you remain curious about the actual magnification of your TC just A-B with and without and then compare results. Minimal rocket science involved. Youll need a ruler. Amazon has a variety. Be sure its metric cuz FL are metric ;-)

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Aug 4, 2022 17:43:03   #
Dan' de Bourgogne
 
imagemeister wrote:
Kenko 1.5X is quite OLD - a holdover from the film era - I tried one on film - very disappointing ! - even when used with a decent lens. Kit lenses especially, do NOT do well with optical extenders - most usually better to optimize your lenses' native IQ and CROP and use pixel enlargement software if needed for larger printing.

Kenko's latest and greatest 1.4X ( $200 +) would be your best optically extending solution.
.


Thank You Imagemeister...I think I will sell this TC...do you think an old (vintage) 300 mm "prime" (not zoom) made by Nikkor could produce better results?

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Aug 4, 2022 17:49:53   #
Dan' de Bourgogne
 
Alphabravo2020 wrote:
I think it will be hard to compare IQ with those exposure settings.

Shutter speeds of 1/80s and 1/20s are pretty long for an outdoor shot at 200mm. Any movement will blur the shot.

Also I think it unlikely that the best IQ is at F/11. The lens is likely to be sharper at f/8 or even lower.

I would want to be closer to ISO 400 for an outdoor shot. I know my D850 is pretty grainy at 1200. A wider aperture will allow you to lower the ISO and also increase your shutter speed.


Thank You for this useful comment. I thought f/11 could be better sharpness and DOF, but i will try at f/8 and 5,6...then compare the results.Today, I shot both pictures from a solid tripod. Anyway, next time, setting f5,6...I should be 2 stops quicker! Thanks for the tips, it'skind of You.

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Aug 4, 2022 17:57:48   #
Dan' de Bourgogne
 
User ID wrote:
Its typical for generic TCs to vary from their nominal magnification. They are mostly impractical except at the most elite level. Youll get better results by resampling in PP.

Even if you just crop to 1.5X, youll still have half your MP which is more than enough for any purpose.

If you remain curious about the actual magnification of your TC just A-B with and without and then compare results. Minimal rocket science involved. Youll need a ruler. Amazon has a variety. Be sure its metric cuz FL are metric ;-)
Its typical for generic TCs to vary from their nom... (show quote)


Thank You for this advice! I think I will sell the old piece of glas and just cropp
when needed...You're right...12 MP are still enough... till 2020 I shot with a D70...6 MP and I was happy!

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Aug 4, 2022 19:04:32   #
CHG_CANON Loc: the Windy City
 
Your lens isn't designed to be extended. You couldn't even connect Nikon branded teleconverters to this lens. The third-party Kenko is not really a good choice either, due to their limitations as well as the lens.

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Aug 4, 2022 23:03:27   #
TriX Loc: Raleigh, NC
 
In candor, I wouldn’t refer to either image as sharp. Why not open the lens up a stop or two and increase the shutter speed a bit as suggested. and reshoot a challenging (high res) subject - one with the TC and one without. Then crop the non TC image to match the size of the TC image and compare at 100%. You’ll know the answer. I like a resolution target for these tests, but the smallest text you can find taped to a wall at a distance is fine, and of course, use a tripod.

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Aug 4, 2022 23:12:35   #
CHG_CANON Loc: the Windy City
 
Dan' de Bourgogne wrote:
Thank You for this advice! I think I will sell the old piece of glas and just cropp
when needed...You're right...12 MP are still enough... till 2020 I shot with a D70...6 MP and I was happy!


A 50% increase is only an effective 300mm for a 55-200mm zoom. Your AF issues are a result of the 1+ stop loss of light when the 1.5x extender is attached. A variable zoom lens with f/5.6 on the long end will get a max aperture smaller than f/8 at the max zoom. Your D7200 does not retain AF at max apertures smaller than f/8.

You could shoot with a 70-300 lens and get better results. Although, 70-300 lenses can't be extended either.

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Aug 5, 2022 06:35:01   #
camerapapi Loc: Miami, Fl.
 
I tend to agree with the statements already discussed here by other members of the forum. The sharpness of an image depends not only on the lens in use but also it depends on our techniques. Your 55-200 is very capable of producing fine images by itself....if we do our part.
Now the image with the tele-converter on. I would not be the first one to test a lens at ISO 1600. The image lacks contrast and if you crop to 50% of its size, adding a small amount of sharpness in post and looking at it at the appropriate distance for such an enlargement it looks pretty good to me. 50% crop is pretty big. I bet a majority of those looking at the image will not find anything wrong with it.

My advise, not different from others is that you use the lens without tele-converters.

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Aug 5, 2022 07:04:41   #
billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont
 
Dan' de Bourgogne wrote:
Thank You Imagemeister...I think I will sell this TC...do you think an old (vintage) 300 mm "prime" (not zoom) made by Nikkor could produce better results?


No.

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Aug 5, 2022 09:05:43   #
jackpinoh Loc: Kettering, OH 45419
 
1. Unless you were indoors, used a tripod, and used a remote shutter release or shutter delay timer, your shutter speed was too low to prevent movement blur.

2. In general, and specifically in the case of old lenses and teleconverters, you are better off cropping the image than using a teleconverter.

Crop the image taken without the teleconverter so that the number of pixels shown on an edge is ⅔ the number it had originally. Compare that image with the one taken with the teleconverter. The difference will show the effect of the teleconverter.

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Aug 5, 2022 10:43:52   #
sippyjug104 Loc: Missouri
 
Dan' de Bourgogne, we can check the focal length of a lens, or a lens with an attachment such as a teleconverter, by setting an object on a table and shining a light on it. Then stand up a piece of white cardboard and lay a yardstick on the table alongside it pointing toward the object.

Hold the lens so that it looks at the subject. Start with it against the cardboard and move it slowly toward the subject. Watch the image that will be projected on the white cardboard. When the image becomes its sharpest, take notice of how far the lens has moved from the cardboard by looking at the yardstick (or tape rule) measured from the camera end of the lens. If the measurement is in inches, convert that to millimeters and that will be the focal length. You should be able to tell the change in focal length of the lens with and without the teleconverter.

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Aug 5, 2022 12:25:22   #
photoman43
 
CHG_CANON wrote:
Your lens isn't designed to be extended. You couldn't even connect Nikon branded teleconverters to this lens. The third-party Kenko is not really a good choice either, due to their limitations as well as the lens.


Agree. I would not buy any teleconverter for this lens.

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