[Dave]

To get extra focal length from my Sigma 70-200mm f/2.8 , I have considered a 2x convertor. I appreciate the loss of F/stops, but I'm more concerned about impact on final image quality.

Anyone have a 2x convertor & can comment ?

[daveyuk]

Yep me

I got one and I'm well chuffed with the results that I'm getting. Have a look in the following
Brands Hatch Photo Gallery by David at pbase.com
Have a look at the last few as I know they've been take with the 70-200 plus 2x tc

Also look at the following
Lowestoft Airshow 2006 Photo Gallery by David at pbase.com
All were taken with the 70-200 plus 2xtc

And lastly take a look at the following
BTCC Sep 2006 Photo Gallery by David at pbase.com
Mainly look at the ones of Druids Bend

I find this combination much better than using my 80-400 as there is less length as the 70-200 doesn't increase in length when you zoom to 200/400mm and less weight even when you add the extra of the 2xtc. I must admit that I have the battery grip fitted as well which gives me a better hand holding area, I'm not sure what it would be like without the grip fitted. I also find that this setup works very nicely when put on my monopod as it feels nicely balanced and very controlable. It sounds daft but I feel I have better control and can use this setup for a greater length of time as I don't feel like my arms want to fall off!! as they do when I use my 80-400mm.

Hope it helps

[Rob Barron]

I think the important thing to remember when buying a TC is that you should approach it like any other lens. Most TCs have at least 3 or 4 and sometimes up to 7 or 8 elements internally so there will always be an effect. How much of an effect depends largely on the quality of the TC purchased.

I used to have a Jessops own brand 2x TC and frankly it was distinctly average. Even on a lens I knew was normally very sharp, images usually suffered from soft focusing, especially at the wide ends of the aperture. However, i got the Canon 2x TC and that problem has all but disappeared. On the one hand the elements used in these are of the same standard used in their L series lenses but on the other hand they cost three times the price! I believe Steve uses a pro range by Kenco which he is also delighted with.

The only true comparison is to take a picture with a 200mm + 2x TC and compare it to a picture taken with a 400mm lens. With the top quality TCs I think you will find the difference to be very acceptable though yes, there might be some lack of sharpness at the widest apertures. You know about the loss of light factors so I shalln't go into those.

The better ones will keep AF on L series lenses at up to f5.6 which is very handy though of course distance work is not exactly hard to manually focus anyway!

Ultimate question: would I buy one? obvious answer, given that I have already said i own one, is yes. I wouldn't use it unless I needed extreme range but i have used it with my 300mm L prime lens to give me 600mm f8 and it is excellent. I don't have a 600mm lens to compare it with and i am unlikely ever to have one! I would definitely go for a quality one though, not sure how much Nikon ones are but the kenco pro one is excellent so is a viable alternative. Steer clear of adding a cheap make onto a quality lens: it WILL make a difference.

Cheers,
Rob

[danpen]

I have the kenko pro 300 and it's good, not as good as a quality long lens but better than not getting the shot. I have used the Kenko MC7 and there is a distinct difference in quality, you get what you pays for.

I used to use the Pro 300 on a Canon 70-200 f2.8, it was good, not quite as good as the Canon 100-400 (go figure) but acceptable. It's OK on the Canon 100-400 too and I'm not going to be buying / carrying an 800mm lens so it serves a purpose.

All I can say is a teleconverter magnifies any imperfections in your lens so start with a good lens, use a good TC and don't expect miracles, used carefully you can get good results.

[Dave]

Thanks for the advice guys. Dave, is that the same Sigma lens as mine & also what make of TC have you got. Some great shots you've captured

[Rob Barron]

Cracking load of pictures there Davey, love the biplanes but I have to say it hurts to see them.... my ONE major 'if I could only ever do one thrilling thing this would be it' ambition is to do a wing-walk on a biplane. I would absolutely give anything to be strapped on top of a bi-plane and do a loop the loop!

And before anyone asks, anything BUT my camera and L series lenses ok!

Thanks for showing the pics, cracking stuff.
Cheers,
Rob

[Steve]

I would just like to add one comment to the above, I use the Kenko Pro 300 converter but it is only the 1.4x and not the 2x version. I chose the 1.4x because I only lose one stop of light and since I partner it with f4 lenses it means that I still retain auto focus.

From my research at the time there are workarounds to maintain AF when using the 2x converter however there is also a bigger trade of in quality loss between the 1.4 and 2x versions that I wasn't prepared to take the hit on.

The bottom line is that a converter (from any manufacturer) will reduce the quality of the shot, some much more than others and usually the larger the converter the bigger the quality loss, however getting a slightly lower quality shot at a range that you normally can't cover is infinitely better than not being able to get any shot. Photography like most other things is all about calculated compromises

[daveyuk]

Originally Posted by Dave

Thanks for the advice guys. Dave, is that the same Sigma lens as mine & also what make of TC have you got. Some great shots you've captured

Dave
I have the Sigma 70-200mm EX HSM and the Sigma x2 TC APO EX.

[daveyuk]

Originally Posted by Rob Barron

Cracking load of pictures there Davey, love the biplanes but I have to say it hurts to see them.... my ONE major 'if I could only ever do one thrilling thing this would be it' ambition is to do a wing-walk on a biplane. I would absolutely give anything to be strapped on top of a bi-plane and do a loop the loop!

And before anyone asks, anything BUT my camera and L series lenses ok!

Thanks for showing the pics, cracking stuff.
Cheers,
Rob

Rob
I understand they are looking for nutters like you

[Steve]

Originally Posted by Rob Barron

my ONE major 'if I could only ever do one thrilling thing this would be it' ambition is to do a wing-walk on a biplane. I would absolutely give anything to be strapped on top of a bi-plane and do a loop the loop!

[VinnyP]

I don't have the Sigma lens but I do have the Nikon equivalent. I use the Nikkor 1.7 times TC but the Kenko Pro 1.4x and 2.0x. I think they measure up well to the Nikon.
I have got a set of pics with the the 300 and 600 with all three covertors which I took in the Autumn. I'll post up these up and I'll try a set with the 70-200 this weekend.

[Rob Barron]

LOL, look guys, I never ever claimed to be normal, sane or compus mentis. I just want to do something really different that is a massive adrenaline rush but falls within the capabilities of my spine (which is riddled with ankylosing spondylitis) to cope. I have done parachuting in the past but am no longer allowed to. I went cash in hand to do a bungee jump but was refused because of my back (I am sometimes a bit crazy but not stupid enough to do something that could leave me in a wheelchair for the rest of my days!). I have done hang-gliding way back in my teens... which led to a terrible accident which left me in hospital for over 5 months, over 28 separate bone breaks and back problems that gave rise to my current condition. I have done adventurous scube-diving and qualified to the level of Club Instructor as well as diving in the Maldives, Red Sea and Mediterranean as well as around the British coast but had to give up because of the pressure the weights were placing on my spine....

So I am not averse to a good rush of adrenaline but sadly there are few activities left that a middle-aged, overweight man can do that don't require massive risk of permanent injury. Yes I know being strapped to a plane doesn't sound too safe either but actually it is. When did you last hear of anyone falling to their death from a biplane?

Oh well, guess I'll have to get my thrills from the click of a button.

Cheers,
Rob

[Dabhand16]

Originally Posted by Rob Barron

I just want to do something really different but falls within the capabilities of my spine (which is riddled with ankylosing spondylitis) to cope.....but sadly there are few activities left that a middle-aged, overweight man can do that don't require massive risk of permanent injury. Cheers,
Rob

As Mrs Barron is not a member, perhaps I can make some suggestions of activities that are really different for a lot of men on her behalf.

1 Washing up.
2 Hoovering.
3 Clean the windows.
4 Ironing.
5 Cook the dinner.

Can't list any more as I've got some washing to put on.........