A 2nd Lens question on IQ.

[dicklaxt]

Would a f/4 300mm prime used with a 1.4 Teleconverter give the same results in Image Quality as a f/4-5.6 70-300 set at 300 and used with a Teleconverter?

I have been looking at some pics of birds taken with the first scenario of the 300 prime and was wondering if my 70-300 would do the same?

dick

[jerryph]

The fast answer is no. Think about this:
Using the 300mm F/4 starting point:
A 1.4 TC will drop you 1.5 stops of light. This is equivalent of getting (F/4 - 1.5 stops = F/6.7 @ 300*1.4 = 420mm).

Your starting point at maximum zoom is F/6.7 @ 420mm.

Do this same calculation using your variable aperture lens:
(F/5.6 - 1.5 stops = F/9.5 @ 300*1.4 = 420mm)

Your starting point at maximum zoom is F/9.5 @ 420mm.

I don't know how often you use F/9.5, but that makes this all but useless in all but the BRIGHTEST of days... and on top of this, a prime always will have better quality results than a mid-range variable aperture zoom.

Take that 1 step higher, if your starting point was a higher quality 300mm F/2.8:
(F/2.8 - 1.5 stops = F/4.8 @ 300*1.4 = 420mm)

A lens that can do F/4.8@420mm vs a lens that can do F/9.5@420mm... which would you think would give you the better results?

There is a reason why anything over 150mm and has a wide apertures is very expensive, but the performance cannot be denied. ;) :)

[coffee]

No. Traditionally a prime lens is going to give much better results than a zoom of the same length. And with the examples that you give, at the far end og the 70-300 your aperture closes down to 5.6. So in the end, the prime will give you better quality and be faster.

[dicklaxt]

ALright, okay.... so I'm getting smarter everyday,thanks guys.Now how do I retain and recall same???smile

dick

[coffee]

ALright, okay.... so I'm getting smarter everyday,thanks guys.Now how do I retain and recall same???smile

dick

I think buying a canon 600L might help you retain the info! hehe ;)

[rasmussen4]

Shoot, just to be sure he should spring for the Sigzilla. If you haven't seen this beast, have a peek.

http://www.letsgodigital.org/images/artikelen/51/sigma_200_500mm_zoom.jpg

[jerryph]

Shoot, just to be sure he should spring for the Sigzilla. If you haven't seen this beast, have a peek.

http://www.letsgodigital.org/images/artikelen/51/sigma_200_500mm_zoom.jpg

I'm not sure, but I believe that this is a 250mm F/2.8 that comes with a 2X teleconverter that brings it up to a 500mm F/4 lens. It goes for about $10,000US.

Quite the beast, but I think I can beat that. Look HERE (http://www.mir.com.my/rb/photography/companies/nikon/nikkoresources/zoomsMF/12001700mm.htm). ;)

1200-1700mm zoom anyone?

[littlepixel]

I'm not sure, but I believe that this is a 250mm F/2.8 that comes with a 2X teleconverter that brings it up to a 500mm F/4 lens. It goes for about $10,000US.

Quite the beast, but I think I can beat that. Look HERE (http://www.mir.com.my/rb/photography/companies/nikon/nikkoresources/zoomsMF/12001700mm.htm). ;)

1200-1700mm zoom anyone?

That thing is insane!