Which is my best option lens or tele-converter

<p>I have an EOS400D and a Sigma DG 70-300mm telephoto. Occassionally I would like to extend my range above 300mm (or 480mm in EOS400D terms) Which is my best option, a behind the lens 1.4 teleconverter, a front of the lens converter (fitting onto filter thread) or go for a new lens? I have a tight budget and affordable lens' are of the manual setting type widely advertised on ebay. On the face of it the 'front of the lens' option appears the best, which if I have understood correctly, retain all the auto settings of the prime lens but I am worried about picture quality. As a relative newcomer to digital photography any advice would be appreciated.</p>

<p>"but I am worried about picture quality" -as well you should be because those front converters are crap. None of the Canon converters will mount on your lens. Look up Bob Atkins' article here on photo.net for some other brand rear converters that may work on that lens, but you may loose auto focus. There is no cheap AND good way to get long. </p>

<p>Your cheapest option is to get closer (wildlife: stalking, use a hide; sports: get a front-row seat, don't try to shoot action at the far end of the field)</p>

<p>Cropping your existing photos and increasing resolution in photoshop will probably give you better image quality than front-mounted converters, and similar image quality than teleconverters. Remember you'll lose autofocus with teleconverters.</p>

<p>Maybe one option for you is to have a look at 500/8 mirror lenses. Have a google, lots of info on this site and elsewhere.</p>

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would recommend a different lens. think prime or high-end zoom

<p>Front adapters simply will not improve the quality of the lens. Not even Canon tele-extenders, even if they fitted on your lens, would make anything "better" The strong likelihood is that either will degrade the image from a little to a lot. Whether you would find it acceptable only you can say.<br>

Long primes are the most obvious, but not necessarily the most convenient option. Long telephoto zooms like the 100-400mm are good, but expensive.</p>

<p>There are older manual focus (and they'd be stop-down too) lenses that can be inexpensively adapted for the Canon EOS bodies (see <a href="http://www.bobatkins.com/photography/eosfaq/manual_focus_EOS.html">link</a> ). Any manual focus Nikon, M42, or some other mounts as well would work. Old Canon FD lenses, however, cannot be usefully used on EOS bodies for their original focal lengths.</p>

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<p>I'd go for a new lens.</p>

<p>You will lose AF if you have a lens or lens and TC combination that is slower than F5.6 (the 1 series bodies go to F8). I cannot comment on the lens but you should look at Sigma teleconvertors. The Canon 1.4x convertor is much better than the 2x (this has been true since the FD days). The 1.4 x canon TC has a front element that sticks out so this restricts it's use to a few lenses. It works well on lenses like the 300 F2.8 and 70-200 f2.8 which is was designed for. On the 70-200 F2.8 the 1.4 x gives a 108-280 F4 which to my eyes performs as well as the 100-400 zoom. The Canon 2x (even the MarkII) is poor - I rarely use mine. As JDM says if you buy an MF lens then Nikon (or M42) are good options</p>

<p>There are a lot of cheap long tele lenses, but few of them are very good. I have found Sigma's 135-400mm and 170-500mm acceptable - not in the 100-400L class, but close, and A LOT cheaper. KEH is currently offering a 170-500mm in ex condition for $299, which is a good deal, and they are an extremely reliable online shop. I trust you would be a lot happier with that lens than with any teleconverter option. If that's out of your price range, cropping your images would be your best option. </p>

<p>If the 170-500 that Frank referenced is still available, get that. It's the cheapest option you'll have for longer glass at a cheap price... $299- for that lens is a _very_ good price.<br>

The bonus is that it's also a step up in image quality from your 70-300.</p>

<p>Thanks everyone. I've got the message - go for a longer lens! The old adage of "If it looks too good to be true............." is about right. The second hand market is a good idea although it appears the one at KEH has already gone so I will keep looking. This is the first time I've used this forum and I have to say that the response is amazing. Thanks again.</p>