Bigma + 2x convertor?

hi there, one of my brothers friends was telling me of how he has fitted a Bigma (sigma 50-500mm) lens with a 2x convertor? Would this actually work? He says that i should do the same as it is amazing? Is this really possible or is he just trying catch me out? Also would there be any draw backs to doing so?
thanks for your time.

Yes, it would work. No autofocus, incredibly small maximum aperture ( f/12.6 )means you would need a lot of light to use it and the optics wouldn't be particularly good... but it would "work".

I tried it when I had a Bigma. As Glen says ...

One thing, if I remember right anyway, you have to set a limiter on the zoom when you have a TCon fitted to stop it hitting the element. But that's no problem. A focus screen would help if you want to use MF with this lens on a regular basis.

so what you're saying is that it would work but it wouldn't be a very good idea? i would need a lot of light and...? Sorry i'm not quite sure i understand.

richardmincher wrote:
so what you're saying is that it would work but it wouldn't be a very good idea? i would need a lot of light and...? Sorry i'm not quite sure i understand.

You'll get pictures but they won't be very good. You'll need to manual focus it, which is hard, and because the aperture is very small at that length very little light will get in. You'll have to up the ISO and slow the shutter speed as a result, which may be Ok with a static object but will cause some blur if the object is moving. You need it on a decent tripod. I'd say forget it.

ok, good points, thanks for all your help. Now that i think about it, it would be kind of difficult, not to mention stupid, lol
thanks again for all your help.

I have a Sigma 50-500 and have used it on my 20D with a Tamron 2x SP AF teleconverter. It is very difficult to get sharp pictures with this combination because any camera movement is magnified. Remember that it is the equivalent of using a 1600 mm lens on a 35 mm film camera. It is necessary to use a very solid tripod, a cable release and mirror lock up. If you are very careful with your technique you can get pictures that will look slightly soft printed 8x10 inches. They are useable, and better than no picture, but would not be considered extremely sharp. I seldom use this combination.

I have had better results with a 1.4x teleconverter on the 50-500.

With either teleconverter you have to focus manually.

richardmincher wrote:
so what you're saying is that it would work but it wouldn't be a very good idea? i would need a lot of light and...? Sorry i'm not quite sure i understand.

"Poop" is the technical term.

Very difficult to get an image you want to keep... image quality is degraded considerably on this zoom lens when used even with a 1.4X T-con.. the 2X looks like "Poop"

I Have a Bigma and do sometimes use a 2x Tcon. I wouldn't really reconmend it personally for the reasons already said. The Bigma eats up alot of light as it is without a Tcon, that said it can be done and you can get "OK" but not stellar images from it. I've taken some ok shots handheld with this combo but the keeper ratio is very low. I still get AF also but I much prefer to MF if I do use the Tcon.

Heres a posting I did on this topic a while back. https://photography-on-the.net/forum/showthre​ad.php?t=114427

For a rare occasion I'd say it's ok, but really not something I'd bother with most the time.

Interestingly, the Bigma + Tamron 2x TC will have limited AF at f/12.6 with the 350D/300D. The four outer horizontal points would still attempt AF, but the top, bottom and center points are dead (as expected). At contrasty subjects, AF with the said 4 points can achieve focus lock, but there's a lot of hunting in low light or uncontrasty subjects.

As to the image quality, here's one of the better pics I got with the combo. You can judge for yourself if this combo is worth setting up. Note that with the cheapo Tamron 2x, EXIF is incorrect as far as Av and focal length are concerned.

300D + Bigma + Tamron 2x, 1000 mm, f/8 natively (f/16 effectively), 1/200 sec, ISO 400, manual exposure, AF using the right-most horizontal point then recomposed:

http://www.pbase.com …e/image/3848319​2/original

Unprocessed 100% crop, JPEG larg fine parameter -1/0/+1/0:
http://www.pbase.com/l​iquidstone/image/38483​400

Regards,

Romy

Well,. I have to admit that is much more impressive than any results I ever got with the combo (using the dedicated Sigma T-con at the time) I got no AF ever with 2X or 1.4X using the Sigma T-cons on 10D (nor should I have)

I did some moon shots with mirror lock up and stopped way down and that was the best use I had.. never worked well with the wildlife.. even a still as a statue great blue, despite getting it decently sharp resulted in an eery loss of color...

I'm impressed..
But still would not recomend it as a very usefull solution.

CyberDyneSystems wrote:
Well,. I have to admit that is much more impressive than any results I ever got with the combo (using the dedicated Sigma T-con at the time) I got no AF ever with 2X or 1.4X using the Sigma T-cons on 10D (nor should I have)

I did some moon shots with mirror lock up and stopped way down and that was the best use I had.. never worked well with the wildlife.. even a still as a statue great blue, despite getting it decently sharp resulted in an eery loss of color...

I'm impressed..
But still would not recomend it as a very usefull solution.

I agree, CDS.... the Bigma + 2x was just a fun combo for me (sold my Bigma since) - very tough to use in the field and needs tons of light. If all variables fall into place, I could get the occasional decent shot, but this was more the exception rather than the rule.

Indeed, there's really no shortcut to get to 1000 mm or beyond with decent quality. If the Bigma works very well at 700 and 1000 mm, I wouldn't have bought my Sigmonster.

If one needs a quality 700 mm or 1000 mm, the better choices are the 500 f4 L IS, 600 f4 L IS or Sigmonster.

But if one already has the Bigma, I'd think there's no harm in trying it out with a TC, if only to hone one's long lens technique....

Happy New Year,

Romy