by mattchase » Nov Wed 17, 2004 9:15 am
I can't speak for Nikon, so most the info below is pertaining to Canon. From my experience with Canon TCs, I would say that the Nikon TCs are probably their equals at the least. This is assuming you buy the best TC from Nikon / Canon, not one of their lower end, works with anything TCs. That is a big thing to watch for, any TC that claims to work with all lenses is probably not worth having. The high quality TCs are designed specifically to work with only a short list of lenses, hence keeping the optical qualities very good.
I have used both Canon and Sigma TCs. There are definitely different grades of TCs out there, and you will want to stay away from any TC that claims it can be used with any lens. Those are the kind that sacrafice quality for compatibility. The Canon 1.4x II and Sigma 1.4x EX APO are both very high quality, they are designed to only work with a very short list of lenses. I have used the Canon extender with Canon lenses, and the Sigma extender with Sigma lenses, but have not tried either extender with the other brands lenses. On their own brands lenses, you will be hard pressed to really see a difference in image quality. It is there, but you will have to blow the images up pretty large and really look for it. The one thing you will lose with any TC is light, the 1.4x TCs lose about 1 stop. I haven't used my TC in a little while, but I don't remember having any focus speed or hunting problems when using my 70-200 2.8 and the 1.4x TC. I've actually been meaning to do a little testing with the TCs at work (we have a 1.4x and 2x, and my Sigma 1.4x), when I do I will post my results.
The 2x TCs tend to show a bit more loss in quality. I would still say it is within reason, and most people wouldn't even notice. The bigger loss is the 2 stops of light when using the 2x TC. If you are on a tripod, or have bright daylight, then this 2 stops probably won't be much of a problem. Also because of this two stops loss, if you are using anything besides a 2.8 lens, your camera will probably not be able to autofocus. Most Canon cameras won't autofocus with a lens slower than f5.6, with the exception of 1 series cameras which can handle up to f8.
I have only used the Canon 2x extender once, and all I can say is wow. I was shooting a panoramic view of the strip from about 12 miles away at dusk, using the Canon 300mm 2.8 lens and the 2x TC mounted, giving me a 600mm 5.6 lens, and my exposures were 1 second at 5.6. I don't have the time to post this final shot right now, but I will, because we just did something with it I would never have thought would work. The original pano was meant to print at about 15"x48", and at that size it looks awesome. All the horizontal and vertical lines of the casinos walls and windows are sharp, very sharp at that size. Last week a client asked us if we could print that same image at 10'x16'...yes, feet. That is 120"x192", compared to the original 15"x48", and this is not for a billboard. They plan on using it as a wall mural to show the view from their condos, so people will be walking right up to this image and looking at it from less than a few feet away. I used Photoshop to interpolate it up in a couple of steps, and made a 2'x3' test print, and am amazed at how well the file held out. There is some softness and loss of detail, but those lines of the casino walls are still there and the windows are easily distinguishable. From 3 feet back, the image looks excellent, and even from only 1 foot away, it still looks really good. What's my point? Two things, one is that a high quality 2x TC mounted on a very high quality lens will give you exceptionally good results, and second is that interpolation has come a long, long way in making moderately large images into huge murals and still look good.
Reference Lists:
The following list is for the Sigma 1.4x EX APO Extender in Canon mount - about $170
(Using this extender with any other lens may damage the extender as well as the lens.)
Sigma Lenses For Canon AF Mode Original Canon EF Lenses Mode
180mm f/3.5 APO MACRO EX HSM MF 200mm f2.8L USM AF
300mm f/2.8 APO EX HSM AF 300mm f2.8L USM AF
300mm f/2.8 MF 300mm f4.0L IS/ USM MF
300mm f/4.0 APO MACRO/HSM MF 400mm f2.8L USM AF
300mm f/4.0 APO MACRO MF 400mm f5.6L USM MF
400mm f/5.6 APO MACRO /HSM MF 500mm f4.5L USM MF
500mm f/4.5 APO EX /HSM MF 600mm f/4L MF
800mm f/ 5.6 APO /EX HSM MF 1200mm f5.6L USM MF
1000mm f/8.0 APO MF 70-200mm f2.8L USM AF
70-200mm f/2.8 EX HSM AF
70-210mm f/2.8 MF
50-500mm f/4-6.3 APO MF
100-300mm f/4 EX HSM MF
120-300mm f/2.8 EX APO AF
300-800mm f/5.6 EX APO MF
And this list is for the Canon 1.4x II (all listed are Canon lenses) - about $280
EF 135mm f/2L USM
EF 180mm f/3.5L Macro USM
EF 200mm f/1.8L USM
EF 200mm f/2.8L II USM
EF 300mm f/2.8L IS USM
EF 300mm f/4L IS USM
EF 400mm f/2.8L IS USM
EF 400mm f/4L DO IS USM
EF 400mm f/5.6L USM
EF 500mm f/4L IS USM
EF 600mm f/4L IS USM
EF 1200mm f/5.6L USM
EF 70-200mm f/2.8L USM
EF 70-200mm f/2.8L IS USM
EF 70-200mm f/4L USM
EF 100-400mm f/4.5-5.6L IS USM
The Nikon 1.4x TC is about $400, and works with the following lenses.
AF-S 80-200mm f/2.8D ED-IF
AF-S 300mm f/2.8D ED-IF (II)
AF-S 300mm f/4D ED-IF
AF-S 400mm f/2.8D ED-IF (II)
AF-S 500mm f/4D ED-IF (II)
AF-S 600mm f/4D ED-IF (II)
AF-S 70-200mm f/2.8G ED-IF VR