teleconverters ?
 

hi all im new here and new to proper photography
i have a canon 350d eos with a tamron 70-300mm lens. id like to get something bigger but cant afford it, i heard about teleconverters apparently multiplying the zoom, if this is right can anyon tell me which one to get for my camera lens combo ? please bare in mind im a total newbie at this

thanks in advance mark

Several points here.
1) Teleconverters multiply the focal length of the main lens but always degrade the image to varying degrees. The more the multiplication the more degradation, do not be tempted by anything stronger than a 1.4 converter for this reason or you will be disappointed.
2) They work best with prime lenses but a 1.4 should be OK with your zoom but there will be some loss of quality.
3) You always lose light with a converter, with a 1.4 converter you will lose 1 stop of light so your zoom will change from a f5.6 to a f8 lens.
4) With your 350D camera this means you will lose autofocus.
This is because any Canon DSLR apart from the professional 1 series will only focus with a lens of f5.6 or faster..
5) Some converters are 'none reporting' which means they do not inform the camera about the change of aperture but even so autofocus would be slow and erratic. Some people mask some of the pins on the converter to make them 'none reporting' but with mixed success.
6) The focus screen will be darker making manual focus quite difficult. Shooting with a long lens has a steep learning curve due to many factors including very narrow depth of field requiring very accurate focus and a much increased likelihood of camera shake leading to blurred shots. The effective f8 does not help here requiring that you use high ISO settings.
As far as makes go it is best to go for a good converter, I would personally recommend the Kenko 300 pro if it is in your price range. Do not let me put you off, I use one myself and get good results but just be aware they are not a magic bullet for cheap long lenses for the above reasons.

thankyou for your in depth reply it gives me plenty to consider, as i say im still learning :)

thanks mark

I bought extender 2x for Canon (arrived yesterday). So far I took only 3 pictures with it. I lost autofocus so I feel like years ago with Bronika and have to practise focusing before I post something into gallery. If I manage to include a picture -see for yourself. I put it together wirth my 100-400 L IS Canon zoom, and was practising to focus on crane opposite, min 1 km away. If I can read something written there. It is not the sharpest image I have ever seen, but for the distance, not too bad. So 400*2*1.6 (for sensor) = 1280 lens.:)

Susan

thankyou for that, thats quite a distance :) i have just ordered a canon 100-400 so ill see how i go with that and definately consider the tele extender

Perhaps this may help those with Canons that loose autofocus when a tele convertor is used. Refers to the Kenko Pro Series. http://www.michaelfurtman.com/taping_the_pins.htm

It would be interesting to do a shot with and without a 2x converter and then crop the shot without the converter to match and see what difference there is in quality.

As a general rule 2x converters will only work well with a fast lens, ideally f2.8 but not bad on some f4's. Primes are also much favoured over zooms. In the Canon tele line up there are only a few super teles that take a 2 x well IMO (400/2.8, 300/2.8, 500/4 and 600/4).
Just my 2p's worth