Criss-Cross pattern with Kenko 300 PRO 1.4 and Nikkor 500mm f4
I've had the manual focus 500mm f4 Nikkor for less than a week and I'm "thrilled to bits" with it. It takes a while to learn to focus constantly and have the left hand on the lens adjusting as needed. My eyesight on the other hand isn't that great now that I'm not as young as I used to a couple of years ago..., but still, I'm sure I will come to terms with this HUGE lens some time soon.
I've been using my Kenko 300PRO 1.4 teleconverter for ages with my Nikkor AF 300 4.5 and the results were and are great both in colour and contrast, but now with the 500 I get this weirdest "criss-cross" effect that I don't like a bit and have no clue why it's happening. The pictures I have added are both crops from the original exposures; one (the robin) without the Kenko and the other with the teleconverter (from 500 I get 700mm).
Has anyone experienced this with the same or other teleconverters? My guess is that as experts say, the teleconverter amplifies the lens defects and the manual nikkor 500, being that old could suffer from this known issue when using it with a teleconverter, more so if it is not an original Nikkor accessory. On the other hand, my Nikkor AF 300 4.5 is also very old, so I'm left quite baffled.
Any comments will be appreciated. Tried to hang a couple of pics with the topic, but it didn't work, so I created a new album in my galleries "criss-cross pattern..." Pls. take a look
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#1. "RE: Criss-Cross pattern with Kenko 300 PRO 1.4 and Nikkor 500mm f4" | In response to Reply # 0ChrisPlatt Registered since 04th Jun 2011Sun 22-Jan-12 09:32 PM
It looks like very harsh and very objectionable bokeh to me, or possibly a combination of poor bokeh and some internal reflections. There is a visible edginess to out of focus elements in the background. The converter and the 500 don't seem to be playing well together.
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#2. "RE: Criss-Cross pattern with Kenko 300 PRO 1.4 and Nikkor 500mm f4" | In response to Reply # 0blw Nikonian since 18th Jun 2004Mon 23-Jan-12 04:57 PM
That's a symptom of an optical aberration, although I cannot remember which one. I'd say that the TC's optical formula is not a very good match for this lens. TCs - even the best ones - often have a fairly significant impact on bokeh. This is not widely discussed, but it's definitely a real-world consideration.
Brian... a bicoastal Nikonian and Team Member
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#3. "RE: Criss-Cross pattern with Kenko 300 PRO 1.4 and Nikkor 500mm f4" | In response to Reply # 2spanishflyer Registered since 25th Dec 2011Tue 24-Jan-12 04:01 PM
Thanks to both for your comments; it seems clear enough that lens and converter don't get along well in this case. I still have to try it out more in detail and see if this unpleasant effect happens in all apertures or gets worse at wider ones. I've only had the 500 lens for a short time so we'll see how it performs by itself and together with a Nikon TC 2x converter which I should get any time now.
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