Looking for a teleconvertor lense 2x or 1.4

Archived from groups: rec.photo.digital (More info?)

"dc" <dcrules01@msn.com> wrote in message
news:1124669655.092500.192020@f14g2000cwb.googlegroups.com...
> I have a tamron zoom lense 70-300mm.I would like to purchase a
> teleconvertor lense to increase the zoom.I was gonna buy the 2x but
> haven't heard good things.Need some input it's for a baseball game i'm
> going to.Will I lose quality in the picture..Any help would be
> great..Thanks

What is the maximum aperture of your lens at 300?
(Just in case you're not sure... It will be indicated with f5.6, or f4,
etc.)

It is most likely 5.6 at the long end (300mm).

Most autofocus sensors in cameras require a certain aperture size for
auto-focus to continue working. When you add a 1.4x tele-extender, you lose
a stop of light, meaning your lens now behaves as an f8 aperture
ens. -This is too little light to allow most autofocus systems to work...so
you need to check this. It is possible that it WILL work, but at f8, you'll
have to have a TON of light to shoot in, not only for AF, but also to allow
fast enough shutter speeds for sports shots. If you're shooting under
bright sun, this shouldn't be a problem...but if you're shooting at a night
game in less than ideal lighting, you'll have trouble. In the latter
scenario, crank ISO way up until you can get the shutter speeds you need.

Also... Teleextenders definitely decrease sharpness in lenses, and consumer
lenses in particular.
1.4 isn't usually too bad, but 2x is a significant optical compromise.
Finally, a 2x decreases the lens aperture two full stops (letting in only
1/4th the amount of light as without it). This most assuredly mean you lose
AF, and you'll be stuck with f11--A TINY aperture to attempt sports shooting
with.

What camera body are you using?

-Mark²

Archived from groups: rec.photo.digital (More info?)

The Cannon digital rebel 300D.So if I understand right the 1.4 is
better than the 2x.It is a day game 2pm to be exact.

Archived from groups: rec.photo.digital (More info?)

"dc" <dcrules01@msn.com> wrote in message
news:1124671282.033556.30380@g47g2000cwa.googlegroups.com...
> The Cannon digital rebel 300D.So if I understand right the 1.4 is
> better than the 2x.It is a day game 2pm to be exact.

You didn't indicate the speed (maximum aperture...5.6?) of your lens.

Unless you paid about $800 for the lens alone, it's 5.6 or slower.
This means you will not be able to use autofocus on your Digital
Rebel...unless you buy a brand fo teleconverter that doesn't communicate in
the standard way with your Rebel. If that's the case, it COULD *attempt* to
AF, but you won't be pleased.

I think a 2x would be a waste of time.

In fact, you may be better off simply shooting with your 300, and then
cropping images down later. ]
This means you'll lose some pixels, but you'll make up for it by enabling
images that aren't totally blurred due to subject motion and slow shutter
speeds (which become necessary at f8 with with 1.4x).