x1.4 versus x2 canon extenders

CJB64

CJB64

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I want to buy some extenders but before I do, could someone tell me what the differences are between them. I would have thought that x2 would be "obviously" better but someone has told me x1.4 would be the better choice :shrug:

Also, if I go for the canon extenders does that mean they wont fit on a sigma lens? Sorry for asking what is probably basic stuff but I dont have a clue. I just see it as a cheaper option to buying a longer lens :lol:
 
With a 1.4 extender you just lose one stop so your 200mm f4 lens would become a 280mm f5.6 with a 2X extender you lose two stops, so it would be a 400mm f8. It is usually reckoned that there is a slight IQ hit when using extenders and stopping down helps improve things, so you need good light as a general rule, or fast ISO's :D

Any extender should fit an appropriate lens though EF-S lenses extend too far and Canon and Sigma TC's won't fit them. I understand that Kenko extenders don't extend past the mount face so can be used on EF-S lenses.

These are a couple of shots with 1.4X and 2X extenders on my Sigma 150-500

http://SPAM/c3whur/jan/Img_0676.jpg

http://SPAM/c3whur/mar/Img_1986.jpg
 
Thanks for that Ken, it actually made sense to me :lol: I think I will go and check out the kenko that you mentioned. At the minute I am now leaning towards the 2x version but it is only tuesday 15.51pm and so who knows :shrug:
 
Remember that with some Canon cameras, you will lose the ability to autofocus if the effective aperture drops below f/5.6, which is why someone may have recommended the 1.4x over the 2x extender.
 
The Canon extenders have a protrusion at the front, which means that they will only fit on a few lenses. Other makes, like the Kenko, don't, so they might be better to look at, depending on what lenses you have.
 
Before you go out and buy a TC, the main question missed so far is what lens do you intend fitting the TC too.......

The canon TC's will only fit to the L series lenses and as mention will only autofocus with lens attached if the combination is f5.6 or less on the XXXXD, XXXD, XXD 5D (both versions) and 7D canon bodies, you can still use the 2x TC, but only manual focusing. The 1D series pro bodies will autofocus upto f8, but only central focus point from f5.6.

The 1.4x TC loses 1 f-stop of light, autofocus speed significantly hit, but no real loss in image quality. (e.g. 200mm f2.8 becomes 280mm f4)
The 2x TC loses 2 f-stops of light, again autofocus speed significantly hit, but this time loss of image quality (detail in the image). (200mm f2.8 becomes 400mm f5.6)

f-stops are f2.8, f4, f5.6, f8, f11, f16, f22 (the ones in between are factions of an f-stop).

The problems you will find apart from wants above is, you will need good light conditions to get the best results using a TC, because you usually have to step the aperture down another f-stop to improve the images.

But the most important question I'll ask again, what lens do you intend to use the TC on, not all lenses will take a TC, so you would need to check whether its compatible with a TC and whether the combination is worth the hassle, especially if you creating a f11 or f16 lens when using the 2x TC.

Peter
 
Manual focussing isn't that hard, we used to do that all the time in the good old days. Probably not so easy for Birds in flight but otherwise not too difficult.
 
artyman said:
Manual focussing isn't that hard, we used to do that all the time in the good old days. Probably not so easy for Birds in flight but otherwise not too difficult.
Click to expand...

For wildlife shots I would agree, I would probably prefer to manual focus wildlife shots than use autofocus, however, if you were using said setup for motorsport or aviation photography, like you birds in flight technique would have to be significantly homed to achieve suitable results....
 
wow guys, soo much information to take in. Thanks everyone for taking the time to post. I currently only have a sigma 18-200 3.5-6.3 lens and a nifty fifty. I would like to buy a 2nd hand lens that would get me "closer to the action" whilst out on walks etc. I have been reading a lot on this forum and searching t'internet but am still a bit bewildered by the choice.

So is it public opinion that tc's are a stop gap so to speak? I only wanted them in the short term until I learnt a bit more about lens's and which one would suit my needs. From what you guys have said, the 1.4x seems to be the better choice for me but now I am worried that it wont fit my sigma :(

As far as outdoors lens is concerned, I have read about the canon 100-300 F4 which would be within my budget. But having had a look at artymans photos I am now tempted by the sigma 150-500 lens. As you can tell, I am a complete "glass noobie" so your advice is greatly appreciated.

Many thanks,
 
I would leave telecons alone for now. They will not work well with your 18-200. They only work well with longer lenses, of very high quality, with low f/numbers. Remember that you lose AF when the f/number goes above f/5.6 with a telecon. I'm not sure you will even get one to fit an 18-200.

A very good longer zoom choice is the Canon 70-300 IS - it's pretty much the mid-budget standard, around £400. Use that as a reference and compare other choices to it.

If you want longer, Canon 100-400L is another lens that's very hard to beat. £850 for a mint used one.
 
Thanks for that Richard, I will have a look at both and try to find some images taken with them. That seems to be the hardest part! As a newbie, it helps me if I can see images to get a feel for how "close" I can get. Just reading technical info with lots of numbers does nt do that :lol:
 
Although Artyman has shown more than acceptable results from his 2x converter, I suspect that had the same shot been made with a 1.4x on the same lens then cropping to produce the same size image would have yielded better results.
The reason for this is that the "2x" designation is a bit of a misnomer in that the 2x refers to focal length and not the image magnification as one might expect. The area magnification is actually 4x. This means the main lens has to be capable of producing 4x the pixel resolution than the sensor can handle in order to beat simple cropping of an image from the same lens without TC, or maybe a 1.4x. This is a very tough call on all but the finest prime lenses. An OEM 200mm F2.8 or 300mm F2.8 prime would most likely benefit but not much else would.
As already suggested, a 1.4x TC will yield useful gains with a sharp medium to long telephoto, even a zoom if they're good quality, but even here you can most likely forget superzooms such as your 18-200mm. A 1.4x TC increases the effective focal length by 1.4x but doubles the pixel magnification.
Which lenses will physically take a TC is another potential sticking point, particularly since the best TCs will fit the fewest lenses. I would rate OEM, Sigma EX, Kenko Pro 300 in that order for quality, but the Kenko would fit the most lenses because its front element is recessed into the mount. I wouldn't bother with anything cheaper than the Kenko Pro 300.
 
eccles said:
Although Artyman has shown more than acceptable results from his 2x converter, I suspect that had the same shot been made with a 1.4x on the same lens then cropping to produce the same size image would have yielded better results.
The reason for this is that the "2x" designation is a bit of a misnomer in that the 2x refers to focal length and not the image magnification as one might expect. The area magnification is actually 4x. This means the main lens has to be capable of producing 4x the pixel resolution than the sensor can handle in order to beat simple cropping of an image from the same lens without TC, or maybe a 1.4x. This is a very tough call on all but the finest prime lenses. An OEM 200mm F2.8 or 300mm F2.8 prime would most likely benefit but not much else would.
As already suggested, a 1.4x TC will yield useful gains with a sharp medium to long telephoto, even a zoom if they're good quality, but even here you can most likely forget superzooms such as your 18-200mm. A 1.4x TC increases the effective focal length by 1.4x but doubles the pixel magnification.
Which lenses will physically take a TC is another potential sticking point, particularly since the best TCs will fit the fewest lenses. I would rate OEM, Sigma EX, Kenko Pro 300 in that order for quality, but the Kenko would fit the most lenses because its front element is recessed into the mount. I wouldn't bother with anything cheaper than the Kenko Pro 300.
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They're the same thing in terms of magnification.

I think the difference in practise is that the telecon introduces it's own optical shorcomings into the equation, whereas, if you have enough pixels and can pull enough resolution out of the sensor without the interference of a telecon, you could get a better result (although simply doubling the number of pixels certainly doesn't mean you get twice the resolution). But as you say, everything hinges on the mother lens being able to deliver sufficient resolution in the first place.

In that sense, I think maybe telecons are a bit of a throwback to film where trying to get that kind of magnification out of a (relatively low resolution) film image was hopeless - the film just fell apart into grain. Hence the popularity of cameras like the 15mp 50D and 18mp 7D for birding, where you often run out of optical reach even with the longest lenses and cropping becomes a viable option even if it's not perfect.

Nothing ever beats having the right lens for the job in the first place though.
 
I think I will go for the canon 70-300 and see what results I get from that. If I still can not get close enough then I will sell it and go for the 100-400. Thanks to all who took the time to post, it has helped me come to a decision.

One last question! Do you think there is much benefit in getting the 1.4x to go with the 70-300 lens?
 
CJB64 said:
I think I will go for the canon 70-300 and see what results I get from that. If I still can not get close enough then I will sell it and go for the 100-400. Thanks to all who took the time to post, it has helped me come to a decision.

One last question! Do you think there is much benefit in getting the 1.4x to go with the 70-300 lens?
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I wouldn't bother. You will lose AF and to be honest with a 50D you might even get a better result by cropping, or at least a reasonably acceptable one.

If you find that you're cropping images regularly as a matter of course, then that'll be the time to get something longer. Anything good will not be cheap though ;)
 
HoppyUK said:
I wouldn't bother. You will lose AF and to be honest with a 50D you might even get a better result by cropping, or at least a reasonably acceptable one.

If you find that you're cropping images regularly as a matter of course, then that'll be the time to get something longer. Anything good will not be cheap though ;)
Click to expand...

Thats saved me a few quid then :lol: thanks very much.
 
KIPAX said:
You know you can buy a sigma 1.4 converter yes?
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Neither of the Sigma EX TCs will fit the cheaper Sigma consumer grade lenses because the front elements of the TCs lie forward of the mount. Any lens that has a rear element that is close to or extends beyond the mount will interfere with the TC and prevent them from locking together. These TCs are designed primarily for EX grade Sigma lenses although they may fit some of the later mid/high-end Sigma telezooms that don't have the 'EX' designation. Best to check the Sigma website if you're not sure.
They may also fit some OEM lenses, particularly those that are often coupled with teleconverters such as large aperture primes.
A Kenko Pro 300 1.4x will probably fit the Canon 70-300 but it's debatable whether you'd see much benefit over cropping your original image.

Edit: I've just checked Photozone for the latest IS version of the Canon 70-300mm and it's a bit of a surprise, bettering the earlier non-IS version by quite a margin. I would imagine a lens giving those sort of figures may well benefit from a Kenko Pro 300 1.4x teleconverter to obtain a little more reach. You will of course lose a stop meaning a maximum aperture of F8 at 420mm. You may just about hang onto autofocus in good light because the Kenko doesn't have a chip that corrects focal length and aperture info. This means that the camera will still assume a maximum aperture of F5.6 and attempt to autofocus. It will no doubt hunt a lot as the light goes down, and not AF at all in lower light levels.
 
Ok my take on this.

The canon TC's don't fit all L lenses. The wont fit my 24-105 for example (not sure you'd want to do this though), also generally speaking, be prepared to lose autofocus unless you have a 1 series (although my lad uses my 70-200 F4 and 1.4x tc on his 400D ok). I wouldn't bother with the taping the pins trick, if it does work it's dog slow.

Now, on my 50D I use the 1.4x and 2x TC with my 100-400 for extra reach.

This was with the 1.4x, manually focussed using liveview
IMG_7679.jpg


This was with the 2x
Moon14.jpg


Recognise the limitations you need to work within and they can get decent pics. Never the same quality as having a fast long prime, but still pretty decent for the cost.
 
Byker28i said:
2x TC with my 100-400 for extra reach....

This was with the 2x
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As of the beginning of this week, I have the same combo, I tried to get a pic of the moon, but I just couldn't get the sharpness I get with the 100-400 on it's own.
Did you use a tripod? as I'm trying hand-held, and I think this is the problem!
 
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