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Teleconverters


jake_levin

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Hi. I own a Nikon D70 and will be getting a 300 f/4 ED lens. I

want to have a teleconverter, 1.7x-2.0x, but I don't know if the

cheaper ones will (a) make the picture softer and (b) disable the

autofocus. What do you recommend? I need something that won't

require a second mortgage, but will keep the picture sharp.

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Jake,

 

The best thing to do is look in the instruction manuals for the camera body and lens and see what teleconverters are compatible with them.

 

The TC-1X E II's, X being whatever number Nikon has there, generally allow AF only with Nikon AFS lenses. If your 300 f/4 is not AFS, you will not get AF function using a Nikon TC.

 

I have heard that Tokina and Sigma and other 3rd party lens manufacturers do make TCs that will allow for AF function with standard AF lenses, i.e. non-AFS lenses. These 3rd party TCs can also be less expensive then the Nikon as well. But you will have to research which ones are compatible with your camera and lens.

 

Another thing to remember, that 300 f/4 is in essence is a 450 f/4 because of the 1.5X magnification factor of the Digital SLR as opposed to a Film SLR. And you got that without loosing any F Stops. Remember also, this applies to all lenses on Digital SLRs from Nikon.

 

Get a B&H Digital Photo Catalog or go online and look on their website to see specs on TCs. If the price for new is too high, look on Ebay for the particular TC you are looking for. You might find the right one at a bargain, but then again that also depends on the demand; it could go for more than the New Nikon.

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I use a D70 and Nikon 300 f/4 ED and have been please with a Tamron SP 1.4 teleconverter. The Tamron and Kenko models are identical and retain autofocus and metering. The TC was about $200 at B&H. They make a lesser Tamron model for about half that much, but I'd stay away from it. Quality varies with the type of lens you use. Generally it's excellent, but I've had color fringing at wider apertures. Here's a recnt photo with the D70 + 300mm f/4 + Tamron SP 1.4X TC.

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<img src="http://d6d2h4gfvy8t8.cloudfront.net/2907750-lg.jpg">

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Not to pick a nit here but,

 

Charlie mad a comment that a 300 is actually a 450mm with the 1.5 crop factor of a digital. Not True.

 

A 300mm lens mounted on a camera with a CROP factor or 1.5 will give you a final image that represents the center portion of a 300 mm image to 450mm. Esentailly you are enlarging a 300mm image 1.5 times. You do not gain any of the benefits of a 450mm lens such as DOF.

 

A 1.7 teleconverter will allow your 300mm lens to become a 510mm lens. When yo mount this on a camera that has a CROP factor of 1.5 you still have a 420mm lens , however you are magnifiying the center portion of that image 1.5 times to give the effect of what a 765mm lens would give you.

 

Note: you really dont have a 765mm lens mounted on your camera all you have is a 300mm lens with an optical element incresing the effective lens to 510mm with a 1.5 CROP.

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Yes, Loren, we know that. The focal length doesn't change. However, what we gain is an end image that, in a given print size (say, 8x10), will appear to have been shot with a lens with a focal length 1.5x longer due to its increased size. However, it's just simpler to say "you'll basically have a 450 f/4" or whatever...we're smart enough to know what he's talking about.
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I've owned the 300 mm f4 AF (not S) and a pair of Kenko SP 300 converters (1.4X and 2X) for some time. The 1.4x is excellent. The 2x is very, very good. (my experience is similar to reviews of Nikon TCs that I've seen.)Both of my converters transmit all info necessary for AF and exposure control. I've used them extensively on an N8008s and an F-100.

 

I just bought a couple of D-70s. The first thing I did was set up my tripod and do some test shots with all my lenses. Everything worked just fine, so I think you can be comfortable with either the Kenko or the higher end Tamron which I understand is the same.

 

Good luck,

 

Bob

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I have both Nikon (older, non-AF) teleconverters and also the Kenko Teleplus Pro 1.4x and 2x. The Kenkos are excellent; I'd recommend them highly. When you shop for a 2x model, the issue of which 300mm. f4 Nikkor you own becomes important. The newest version of the Kenko teleconverter will autofocus with AF-S lenses, but the previous model(s) will not.

 

As for buying one used, these go up for sale fairly regularly through ebay (where I got mine).

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Jack, the best way to save money is to get a new Kenko PRO-300 1.4x or 2x converter. I take it that the 300mm f4 ED is the older mechanical "screwdriver" AF and not a newer "motor in the lens" AF-S? In this case, you can't use the excellent Nikon TC-14E or TC-20E converters.

 

The PRO-300 will "future proof" you. It will work with pretty much any screwdriver lens. If you acquire an AF-S or AF-I lens at some point, it will work fine. (The 400mm f2.8 AF-I can sometimes be found used at a pretty good price, and is an amazing lens).

 

The MC-7 is good, almost as good as the PRO-300, but it won't work with a lot of current lenses (although it will work with a screwdriver 300mm f4).

 

You won't find an acceptable 1.7x converter. The only decent one on the market is the Nikon TC17E, and that gem will set you back $450 or so. And it won't work on a screwdriver lens. It's hard to believe, but the Kenko PRO-300 converters (also sold as the Tamron SP-AF converters) are the only really decent non-Nikon converters on themarket for a Nikon AF system).

 

I would recommend starting our with the 1.4x. That makes a 300mm f4 into a 420mm f5.6. Your D70 will still focus with an f5.6, although you want to make extra effort to center the AF brackets on something with a lot of contrast, and bright light helps. The 2x would give you a 600mm f8, which will lead to much misery with the D70 viewfinder. And manual focusing a D70 isn't easy. If you're going to try a 2x, I would suggest getting a Nikon DG-2 flip up magnifier to help you with focusing (or a Contax 2x flip up, or a Canon angle finder C, all of which work on your D70).

 

Remember, after you count the 1.5x magnification of the D70, you're dealing with either 630mm f5.6 or 1200mm f8. This is "telescope" territory. You need a really solid tripod, and solid head to damp vibrations and give you sharp pictures. The biggest reason people go "teleconverters aren't sharp" is because they don't take this into consideration, that their camera support isn't good enough for a lens that's suddenly twice as long but 2 stops slower.

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Loren - first that "pick a nit" comment, following John's picture, is hilarious.

 

But on a more serious note, the camera's crop factor affects DOF exactly the same way a teleconverter does. Both a TC and a crop do exactly the same thing, they take a central portion of the image and spread it out over a large area. Both enlarge the "circles of confusion" so that areas that were close enough to the focus plane to appear "in focus" without the magnification are suddenly enlarged enough for you to see they're out of focus.

 

So, if you put a 300mm f4 on a 1.5x crop camera, you've got the perspective, field of view, and DOF of a 450mm f6.0 on film.

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