Sigma 50-500mm and a converter
 

Hi
Happy new year.
Using a Nikon D200 and the Sigma 50-500mm 1:4-6.3 AP0 DC HSM D lens with a KENKO N-AF 1.5 teleplus SHQ converter what focal dissidence will it give me I normally shoot at ISO 400 in good light I can shoot at f4 ok, so with the KENKO N-AF 1.5 teleplus SHQ converter upping ISO to 800 will I be able to shoot a f4 If no what would be the ISO to shoot with the converter to shoot at f4 I hope this make sense
Hugh

The ISO is immaterial, in that you will lose 1 stop with the converter, making your minimum aperture f5.6

Depends what you are shooting, but in anything other than good light your lens will 'hunt' around. There are others on here more qualified than me to comment, but I don't think the above is a good combo.

Your focal length with a 1.5 tc fitted will be 1.5 x whatever length you set the zoom at. So at the 500mm end the focal length will be 750mm.
With your camera you will also have a crop factor which will alter the Field of view but this should not be confused with an increased focal length.

I do not have this lens but have read reports from users who say that image qualilty is badly effected by adding a tc.

As Derek as already said ISO does not come into it.

Hugh,

Adding the 1.5x teleconvertor will lose you one stop of light. As Derek has said, this will make your lens effectively f/5.6, but this is only at the 50mm end of the focal length. The maximum aperture of this length varies as the lens is zoomed, which is why it is described as 1:4-6.3

This means that the wide open aperture at the 50mm end is f/4 but at the 500mm end, the maximum aperture (without the teleconvertor) is f/6.3.

Adding the 1.5x convertor loses you one stop of light which makes your lens f/5.6 at the 50mm end, but a rather poor f/9 at the 500mm end.

Duncan

Hi Derek, Roy, Duncan
Thank you all, it was just a thought to try and gain focal length on my 500mm lens
Hugh
http://hughsphotoshop.com/

Duncan's concept is right as always but a small glitch.
I am not sure about kenko's TC as I don't have that but when using my 50-500mm with Sigma's 2x TC, you lose a physical length of lens from lower focal length, due to protruding opticals in TC, into true hallow end lumen of lens, so in effect, you can have the benefits of 2x only from original 100 to 500mm focal lengths and you lose the 50-100mm of original (Non magnified) lens' focal length.

You do loss some quality (Not too much though) with converter, but it's up to situation and you to decide if it worth.

Nevertheless this is one very very unique lens that seems to keep its place firmly despite several years of manufacturing as no other company even the giant ones, have dared to make a competitor in this range.

Two things I don't like about the lens:
1- Squeaky sound sometimes comes out of motor while AFing but it seems to be a benign sound that needs to be tolerated only.
2- Large filter size that makes every filter virtually a wallet destroyer and lack of rear end slot for smaller drop in filters.

Otherwise one wonderful lens that makes you quit proud when in use with exceptional result most of time.