lens extensions.

Briony

Briony

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I have the Sigma 120 - 400 lens, I am very interested in wildlife photography and was wondering if I could get extension tubes for this to make the focal length longer? if I can which ones would you recommend?

I really cannot afford to buy another lens with a longer focal length:thumbsdown:
 
The 120-400 will accept the Sigma x1.4 and x2.0 teleconverters, but both will require you to manual focus, and there will be a loss of image quality.

Or you could crop and retain image quality at reduction in pixel count.
 
Briony said:
I have the Sigma 120 - 400 lens, I am very interested in wildlife photography and was wondering if I could get extension tubes for this to make the focal length longer? if I can which ones would you recommend?

I really cannot afford to buy another lens with a longer focal length:thumbsdown:
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They're not called extension tubes, thats something completely different, extension tubes increase the magnification of the lens and are used for macro photography, what you want are teleconverters (TCs).

Yes the 120-400mm f4.5-5.6 will take a TC. You do realise though that you'll only be able to manual focus this lens, you lose 1 f-stop of light with the 1.4x TC which will create a 168-560mm f5.6-f8 lens and 2 f-stops of light with the 2x TC which will create a 240-800mm f8-f11 lens, so you need very good light to use the 2x TC and you'll also lose a significant amount of image quality with the 2x TC.

Would recommend the sigma TC's
 
So I am better to get in closer where I can then or buy another lens!
 
Extension tubes are a cheaper means along while dioptic filters to access macro photography with your current lenses, but to get true macro shots, you'll need something like a tamron 90mm f2.8 macro lens.

What I was saying about working distance is the 70-200mm has a minimum focal distance of 1.2m where as say the tamron has a minimum focal distance of 29cm's so you'll need to take that into account when setting you shot up. There are people who successfully use extensions tubes and the 70-200mm lens or something like a 50mm prime, the lens doesn't have to be a macro lens, just understand you limitations when using them.
 
What sort of wildlife photography in particular interest you Briony and when do you find the reach lacking?

I only ask as I have been considering the Sigma 120-400, but do wonder whether I'd always be wanting a bit more reach and should go for one of the 500's instead.
 
pete s said:
What sort of wildlife photography in particular interest you Briony and when do you find the reach lacking?

I only ask as I have been considering the Sigma 120-400, but do wonder whether I'd always be wanting a bit more reach and should go for one of the 500's instead.
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That in lies the problems of the longer lenses and the fact that most wildife photographers move away from zoom and go for prime lenses, unfortunately $$$ also becomes a major factor as well.

The xxx-500mm sigma offerings are f6.3 at the top end, and usually soft wide open, so you would need to step them down to obtain the best from them, as long as the light conditions allow you to do this.
 
I have tried the 1.4x TC with both the 120-400 and 150-500 and I would not suggest you using one as the loss in quality and light was noticeable and you lose AF which is important IMHO
 
Briony said:
So I am better to get in closer where I can then or buy another lens!
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Get closer.

Learning good fieldcraft is generally free and can get you excellent results that would still be impossible with longer lenses.

You might have to spend a bit of money on supplies (Hide & other camo gear) but it will be much cheaper than a new lens.
 
pete.rush said:
Extension tubes are a cheaper means along while dioptic filters to access macro photography with your current lenses, but to get true macro shots, you'll need something like a tamron 90mm f2.8 macro lens.

What I was saying about working distance is the 70-200mm has a minimum focal distance of 1.2m where as say the tamron has a minimum focal distance of 29cm's so you'll need to take that into account when setting you shot up. There are people who successfully use extensions tubes and the 70-200mm lens or something like a 50mm prime, the lens doesn't have to be a macro lens, just understand you limitations when using them.
Click to expand...

I cannot seem to get closer enough to my subject here that is why I was pondering the extra length but was advised against the 500 becasue of the poosr quality.
 
RichardtheSane said:
Get closer.

Learning good fieldcraft is generally free and can get you excellent results that would still be impossible with longer lenses.

You might have to spend a bit of money on supplies (Hide & other camo gear) but it will be much cheaper than a new lens.
Click to expand...

Yep more or less decided on this hence my other posts about hides etc, but am off to the USA in June and will probably pick up some gear cheaper over there.

In the mean time will be practising my "up close and personal" here :lol::lol:
 
You don't lose that much IQ with a 1.4 attached to a Sigma 150-500, results can be perfectly acceptable. This is a pretty big crop from such an image the insert shows the original. This was without a tripod as well!

Img_0166c.jpg
 
artyman, you've used this image quite abit to visualise the 150-500 + 1.4x TC, but to be honest, this ain't a good example, the subject is still too far away for that combination, the image is soft and not totally in focus. I accept that in the right conditions this lens will take a good image, but there are better examples than the one you keep posting to portray that, sorry to be brutally honest...

sigma 170-500mm
http://www.talkphotography.co.uk/forums/showthread.php?t=207272

sigma 150-500mm
http://www.talkphotography.co.uk/forums/showthread.php?t=176444&highlight=150-500mm

sigma 150-500mm
http://www.talkphotography.co.uk/forums/showthread.php?t=134325&highlight=150-500mm

Peter
 
RichardtheSane said:
Learning good fieldcraft is generally free and can get you excellent results that would still be impossible with longer lenses.
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"Fieldcraft" is sometimes just not practicable.
 
Peter I know the subject is a long way away, but frequently those are just the times when you are up against it, I was just attempting to show that you can get an image at long distance that's all. Would you prefer this one.

http://SPAM/c3whur/jan/Img_0655.jpg
 
May I ask why a TC will not auto focus on the 120-400?

The Canon 2x works with my Sigma 120-300.

Is it the electronics in the 400 preventing it from working?
 
snoop69 said:
May I ask why a TC will not auto focus on the 120-400?

The Canon 2x works with my Sigma 120-300.

Is it the electronics in the 400 preventing it from working?
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If it is a f2.8 lens then adding a 2X takes it to f5.6 which means AF will still work. Any higher and it won't.
 
artyman said:
If it is a f2.8 lens then adding a 2X takes it to f5.6 which means AF will still work. Any higher and it won't.
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Thank you :thumbs:
 
snoop69 said:
May I ask why a TC will not auto focus on the 120-400?

The Canon 2x works with my Sigma 120-300.

Is it the electronics in the 400 preventing it from working?
Click to expand...

As artyman said, its all to do with the f-stops you lose when attaching the TC to the camera. canon 1.4x TC would lose 1 f-stop, the 2x TC loses 2 f-stop of light.

So the sigma 120-300mm f2.8 + 2x TC would create a 240-600mm f5.6 lens.

F-Stops f2.8, f4, f5.6, f8, f11, f16, f22 are all true f-stops..... f6.3, f5, f7 are parts of an f-stop.

So by adding a 2x TC to the 120-400mm f4.5-5.6, it creates a 240-800mm f8-f11 lens. For canon all the models except the 1D series won't autofocus with lenses or lens combinations above f5.6. The 1D series will autofocus upto f8, but only centre focus point from f5.6-8.....
 
Thanks Pete, many thanks :thumbs:
 
fracster said:
"Fieldcraft" is sometimes just not practicable.
Click to expand...

Absolutely right, then you do need the longer glass. But since it is sometimes not practicable then many times it will be.
 
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