extend range

[quintr0]

 i have a canon t1i rebel with a 300 tamron lens i use for birding what is the best way to extend my range so i can take pictures of hawks? i do everthing on automatic.

[Skirball]

There isn't a good way, that doesn't cost money.

Getting more reach, with good picture quality, has always been the lust of many photographers.  For most it remains a dream, others hand over large sums of money (thousands, to tens of thousands).  As an aside, it's probably the one element of photography that hasn't really changed over the years.  Everything else has gotten cheaper, quicker, easier, better quality.  But getting good long lenses is still just plain expensive.

You could get a cheap-ish longer lens.  I can't recommend any that cost much under $1000, but I'm sure some exist.  Sigma has a 150-500 that costs a hair under $1000, and Tamron makes a 150-600 that is a bit over that mark.  Going to a name brand like Canon and you can put another zero on there.

There are also extenders, a 1.4x and a 2x, but they come with severe penalties.  First they cut out half the light, which can lead to autofocus problems (if your camera can autofocus at all with an extender on).  And they can have significant impact on the image quality.

In summary: there is no perfect answer.  And everybody has their own opinion on what is satisfactory image quality and performance.  Maybe you'd be happy with a cheap telephoto, maybe you'd be happy with a mid-range one.  Maybe you'd be happy with an extender (I seriously doubt it).  But most the people who are going to give you an opinion on here have a pretty high bar when it comes to these things.  Most of us have many, many thousands invested in our cameras already.  So just keep in mind who is giving you advice.

[TCampbell]

You could buy a Tamron 150-600mm and that would probably be the most practical solution to the problem.  But attempting to extend the range of your 300mm will probably not work at all ... much less work to your satisfaction.

The way to extend the range of a lens is with a tele-extender.  It turns out you cannot use a tele-extender with just any lens... only certain lenses work with them.  The tele-extender is an adapter that fits between the camera body and the lens and they come in 1.4x and 2x versions.   A 1.4x means you multiply the old focal length of the lens by 1.4 and you get the new focal length... so 300 x 1.4 = 420.  That sounds great... until you find out that it ALSO changed the focal ratio by 1.4.  If you had a 300mm f/5.6 lens... now you have a 420mm f/8 lens (this is not good).

And you might be wondering why that matters... the auto-focus system uses a prism to split the light into two halves in order to do phase-detect auto-focusing.  The higher the focal ratio, the more difficult it is to make that system work at all.  VERY FEW cameras can auto-focus at f/8.  The 1D X can, the 5D III can, and the 7D II can.  That's it... nothing else in Canon's current lineup would be able to focus at f/8.  (and the 2x tele-extender would turn it into a 600mm f/11 lens -- even worse.)

The reason they make these 1.4x and 2x tele-extenders is because low-focal ratio lenses can use them.  I have a 300mm f/2.8 lens.  I can use a 2x teleconvert and that turn it into a 600mm f/5.6 lens -- and every Canon EOS camera can focus at f/5.6 so that's no problem.  The image quality isn't as good as using a real 600mm lens, so there's no free lunch in that regard, but it can be done in a pinch.

[quintr0]

thank you all for sound advice, being a novice it sure is good to have some handy help before shelling out a fistfull o dollars

[quintr0]

would a 500 mm mirror lens work, got it for free,need an adapter. the adapter is a vivitarf/8 manual focus?

[ScottyP]

Mirror lenses are pretty awful. Google donut bokeh. All the out of focus highlights show up as little ghostly Cheerios. Very distracting.

Also any adaptor would probably kill autofocus so you'd be trying to focus manually.

[TCampbell]

Mirror lenses are cheap -- these are "catadioptric" lenses and use Schmidt-Cassegrain type optics.

The lens has a front corrector with a central obstruction.  The back of the lens has a spherical "primary" mirror.  The central obstruction holds a secondary mirror and this bounces the light forward into the camera.

There usually is no aperture control.

The central-obstruction may cause a "reverse vignetting" effect because while the camera cant focus on the central obstruction, in bright light it will tend to slightly dim the central area of the image.

Anything out of focus will de-focus in the shape of the clear part of the aperture... which is actually "donut" shaped -- which creates a reallly wonky (awful) "bokeh" effect.

The lenses typically use a t-mount and require a camera-specific mount adapter (aka "t-ring").

They are cheap because they typically have no electronics of any kind, no aperture control, and just a manual focus (which moves the primary mirror forward or backward to focus.)

The adapter you need should most likely be "T-Mount to Canon EOS" mount.  It's just a ring that has the bayonet type mount of the camera facing side... and the t-threads on the lens-facing side.  It'll probably cost $10-15.

The attracitve thing about these lenses is that it's a VERY affordable way to get a very high focal length lens.  But the downside is that there's no electronics, no auto-focus, no aperture, and you wont like the quality of the out of focus areas.

[quintr0]

once again thanks for the help, looks like i will be saving up my pennies for a tamron or like lens.

[ebiggs1]

Nix the tele converter idea.  Also nix the mirror lens thought.  Absolutely the best buy in a super telephoto right now is the Sigma 150-500mm f/5-6.3 APO DG OS HSM.  It has a $200 rebate and makes it cost $869.  Excepth for 500mm vs 600mm it is as good as the Tamron 150-600mm which nearly $1100.

I have both but very much prefer the Sigma.

[ebiggs1]

" i have a canon t1i rebel with a 300 tamron lens ..."

You didn't ask but besides the lens you absolutely need a post editor.  I use Photoshop but there are others.  Some are even free but much lesser that PS.  Photoshop Elements is a very good option and doesn't cost a bunch.

Remember you photo is only 1/2 made in the camera.  The other 1/2 is in post.