AF 2x TC with AiS CPU Lens

[girishmenon]

<p>Hi, if I use a Kenko Teleplus PRO 300 AF DGX 2.0X teleconverter on the 500mm f/4 IF-ED AiS CPU fitted lens on a Nikon D300, will the 'electronic rangefinder' work as it should?<br>

In the past, I have used a TC-14B (Nikon 1.4x non-CPU teleconverter) along with a Neewer Nikon-Canon EOS adapter with focus confirmation chip on a Canon body and that worked great. </p>

[kari_oinonen]

<p>The 'electronic rangefinder' -function doesn't seem to need electrical connections between the camera body and the lens.<br>

However those lens electronics seem to have lens specific focus correction parameters - for a reason, i guess.<br>

I tested with D700 + 2x manual nikon TC + afs 300/4 lens. Yes, those arrows and the ball were there. If your D300 has af-fine tune, I'd check if tuning is needed.<br>

The setup I tested does fork well, but only on near subjects. Focusing more than 20 meters away results useless IQ.<br>

Anyways you will get a 1000/8 lens system. This means not too much light, and maybe too much vibrations. Add the DX factor and challenges are even bigger.</p>

<p> </p>

[Andrew Garrard]

Hi Girish. Yes, you'll be fine - Nikon's digital rangefinder

(autofocus confirmation) doesn't require any electronic

communication with the lens, unlike Canon's. You won't

have focus distance transferred to the camera, so you'll

get matrix metering but not 3D matrix metering, but the

500 f/4 AI-P doesn't transfer this anyway. If you have

problems with the electronics you may have to fill in the

"non-CPU lens data" menu on your camera to avoid

being stuck at spot metering, but I suspect it'll just work.

My 500 f/4 AI-P works fine with a TC-14E with the tab

filed down so that it physically fits. I have trouble with

my TC-16A, but that was incompetent modified (by me)

to work at all, so I'm not too fussed. I assume you're not

expecting autofocus. If you do, the TC-16A is your

friend, but the optics aren't brilliant.

[Andrew Garrard]

Oh, wait, Kari's right - electronically you're okay, but f/8

is asking for trouble. It *might* work, but I don't believe

it's specced to. The f/6.3 or so that a TC16 provides

seems okay on a D700, but f/8 is pushing your luck.

Choices - upgrade to a D800 or stick a TC14 on a 600

f/4... or just try it and rely on live view if it's no good.

[Andrew Garrard]

Incidentally, I have a relatively cheap Dobsonian

telescope that's roughly 1250mm f/5. I've not checked

the digital rangefinder to see if the mirror system

messes with it, but it might work. If you're desperate for

a very long and cheap lens, it might be worth a look. It

makes the 500mm look portable, though.

[girishmenon]

<p>I tried the TC-14B on the D300 with this lens, but the 'electronic rangefinder' didn't seem to work even in bright daylight! I'll try again. </p>

[Andrew Garrard]

Girish - that's odd, f/5.6 from the f/4 + tc14 should

definitely be fine. Do report back. Is the camera seeing

the lens aperture settings at all? Does the rangefinder

work with the bare lens? Good luck.

[girishmenon]

<p>Hi Andrew, yes all apertures work as they should, the rangefinder works beautifully with the bare lens. It didn't seem to work with the TC-14B but I'll try again soon. Someone messed around with my gimbal head and I had to send it off for repairs. </p>

[Andrew Garrard]

<p>Hmm. Okay, for so long as the lens and teleconverter combo is faster than f/5.6, I'm out of reasons for there to be trouble. Sorry, I've run out of expertise! I'll be interested in the results of a repeat experiment, though - maybe there's something odd that you'll only spot on the second attempt. Good luck.</p>

[girishmenon]

<p>Thanks, Andrew. I'm planning a trip soon and hope to have this working before I leave : )<br /> Some months ago, I had tried this lens + tc on Canon cameras and had posted the results here: http://www.photo.net/canon-eos-digital-camera-forum/00cUgN<br /> But then a month ago, I had gone on a trip to the desert and tried the lens + tc on a Nikon D300 before I left, but it didn't work. So I used the D300 without the tc to make these photos:</p>

<p><img src="https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xpf1/t31.0-8/10604598_685580801531782_2878589564023853501_o.jpg" alt="" width="1024" height="680" /><br /><br /><br>

<img src="https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-xaf1/t31.0-8/10626296_685636101526252_8526364836757680885_o.jpg" alt="" width="1024" height="768" /><br>

Sorry about the watermarks... just copied the image link off facebook :)</p>

<p> </p>

[Andrew Garrard]

<p>Very nice, Girish. Sorry I don't have a good suggestion for the teleconverter! (Of course, if you could live with a D7100 instead, the extra pixel density would do some of the job for you...)</p>

[girishmenon]

<p>Thanks Andrew. I checked the setup this morning and 'electronic rangefinder' indeed works with a TC-14B!<br>

In the past, I was looking for the AF-point to light up and didn't pay attention to the little green circle at the bottom of the viewfinder. This is a relief. I can now consider the TC-301 rather than the expensive AF ones. <br>

Thanks : )</p>

[Andrew Garrard]

<p>Ah - yes, no illuminating AF points, especially not in the Canon style of "group AF" lighting up any that happen to be in focus (although I hear they may not do that any more - shame, it was useful). Partly because the D300s and above have a three-component AF confirmation to tell you which way to turn the focus ring. A long time back, I did suggest to Canon and Nikon a blinking pattern that would sensibly provide this information while keeping the AF points visible, but they don't seem to have gone with it. Good luck with a 2x TC, but it's good to know that at least the TC14 works.</p>

[girishmenon]

<p>Thanks Andrew : )</p>