Teleconverters

10 posts / 0 new
Last post
Devster
Devster's picture
Teleconverters

Hi guys

Just wanting to know what peoples thoughts are on teleconverters?

Do you lose to much quality just to gain some focal length or are they worth investing in.

If so, what size do people prefer?

Love to hear your thoughts.

Cheers

Devster

saturnv78
saturnv78's picture

Hi Devster,

Don't want to tell you something you already know but in case you dont know I'll post here anyway! The main consideration when using a teleconverter is that the speed of the lens will decrease in proportion to the magnification of the teleconverter. For example, if you are using a 300mm f4 lens and put a 2x teleconverter on it, the focal length will increase to 600mm smiley, but the lens will now have a best apeture of f8 sad.

With this in mind use a 2x teleconverter only with a lens that is f2.8 or faster. For a lens between f2.8 and f4 consider using a 1.4 teleconverter and with a lens slower than f4 best not to use a teleconverter.

With a good lens and a good teleconverter you wont lose too much image quality, its the speed you lose that is more significant.

Hope this helps smiley

Devster
Devster's picture

I knew nothing about teleconverters so It has helped heaps, thanks saturnv78!

Devster

rawshorty
rawshorty's picture

Don't forget that unless you have a high end camera you will NOT have auto focus with greater than f5.6.

I have used my 1.4 Kenko on my 1diii and Sigma 150-500 with good results but i don't think it is worth the loss of af speed.

Shorty......Canon gear

Canberra

http://www.flickr.com/photos/rawshorty/ 

pacman
pacman's picture

I am a Canon user and have a 2nd hand 2x for sale.

But seriously I have both 1.4x and 2x, I used the 2x a number of times and was not happy, a better photographer would be able to be more explicit on the reasons. It was used on a f2.8 and f4

Peter

Devster
Devster's picture

If I get one I will probably get a 1.4x not experienced enough for the 2x

Reflex
Reflex's picture

This was taken hand held with a 300mm Canon f4 with a 2x this morning. Should add that I threw quite a few away as well....it was just on the camera at the time.

Samford Valley Qld.

Reflex
Reflex's picture

 A couple more taken this morning with the 2x on but under pretty much ideal conditions and with a tripod.

I have had some really mixed results with the 2x and it spends most of its time in my camera bag but I'll keep it.

Samford Valley Qld.

Canonguy
Canonguy's picture

devwenbull@hotmail.com wrote:

Hi guys

Just wanting to know what peoples thoughts are on teleconverters?

Do you lose to much quality just to gain some focal length or are they worth investing in.

If so, what size do people prefer?

Love to hear your thoughts.

Cheers

Devster

What lens are you putting one onto? I would steer away from most zoom lenses except a few Canon or Nikon Pro grade zooms. 

The most important thing is to use a main (prime) lens of the highest quality with (brand) matching converters (Eg Canon for Canon etc). Converters lose light, 1 stop for 1.4x, 2 stops for 2x or about 1 2/3 stop for a 1.7x (Nikon). So you lose shutter speed meaning you would need to use higher ISO to increase shutter speed for more magnification. However, many of the lower end cameras do not perform well at higher ISO values.

Most people will be happy with whatever they can get, but in the end you get what you pay for.

My EF 500/4L IS USM takes a 1.4x perfectly with little if any loss of image quality. Takes the 2x well with some loss of image quality that can be managed sufficiently with user experience and under the right light will take great shots with stacked 1.4x and 2x converters at a focal length of 1,400mm. I have no problem using any and all my converters. Practice makes for good results.

Mind you I use Canon 1D series bodies, so they AF (center point only) even with 2 converters stacked together!!!!! Not that AF matters with static subjects mostly. It does help somewhat. 

Here is a sample of 1,400mm focal length shot in perfect conditions with good technique. The RAW files have incredible detail and these are full frame images processed with Photoshop. That means I was just under 6 meters from the bird!! The biggest mistake people make with converters is they stay far away expecting the glass to do the ground work then complain the converters are rubbish.  Another example of poor tradesmen blaming their tools. 

Converters are only as good as the lens they're attached to and the user behind the camera. 

https://www.flickr.com/photos/105582591@N02/11040546765/in/set-72157636747781405

https://www.flickr.com/photos/105582591@N02/11040733543/in/set-72157636747781405

https://www.flickr.com/photos/105582591@N02/11040546625/in/set-72157636747781405/

MrBean
MrBean's picture

There's a few things to weigh up:

  1. A teleconverter will have some effect on IQ - as there's more glass in the focal path.
  2. To compensate for the loss of a stop or two (1.4x TC or 2x TC) perhaps the ISO needs to increase, thereby increasing possible image noise.
  3. A larger image size means more pixels covered. Eg: double the image size and 4x the number of pixels are covered, which is good, as point 2 maybe a non-issue.

On occasion, I use the 1.4x TC on a 300mm f4 lens. Usually it helps, but, there are times when I can see a loss of IQ. Stopping down half or one stop helps for my setup.

 and @UrbanBirdsOz  @birdsinbackyards
                 Subscribe to me on YouTube