Time to be with your loved ones

Time to be with loved ones

by sat

submit your photo


Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

Take the 2-minute tour ×
Photography Stack Exchange is a question and answer site for professional, enthusiast and amateur photographers. It's 100% free, no registration required.

I'm a beginner at photography and own a Canon 20D with two lens; a 50mm prime and a 17mm-85mm zoom.

I've purchases all my filters at 67mm to fit my zoom lens and use a 52mm - 67mm step up ring to use them with my prime lens.

I'm looking at buying a wide angle lens. My question is, will the same principal work? Can I buy a 67mm wide angle lens and use it on my 52mm prime without any trouble.

One of the reasons for the purchase of a wide angle is my cropped sensor makes the 50mm prime rather close - I'm hoping the wide angle will make it easier to capture more.

Many thanks for any help in advance.
Pete

share|improve this question
    
    
Also kind of related (on the telephoto side): What is a “2.2X Pro Telephoto” lens? –  mattdm Aug 12 '13 at 9:29
add comment

2 Answers

up vote 7 down vote accepted

First off, although the sellers label it as a wide angle lens, in reality what you are considering purchasing is more properly called a wide angle conversion lens because it screws onto and converts your existing lens to cover a wider field-of-view. In general the products sold in this price range aren't very good, and that is putting it nicely. There are some more expensive wide angle conversion lenses, such as those made by Raynox, but the largest size I'm aware they make fits on 58mm threads. And even those involve a fairly significant compromise in image quality.

The step up adapter should work on your 50mm lens, but I would be very surprised if the image quality were even anywhere near as good as your 17-85mm zoom zoomed to around 35mm. The magnification provided by the conversion lens is listed as 0.45x which should produce a field of view of around a 33-35mm lens when combined with a 50mm lens. Remember magnification is expressed in terms of coverage area, not focal length. In return for that modest improvement in angle of view, you will almost certainly see a substantial increase in vignetting, distortion (the fish-eye effect), and chromatic aberration (color separation that makes objects near the edge of the picture look blurry). Here is a well written review of a similar lens that goes into far more detail and provides test shots comparing using a wide angle conversion lens with a wide angle lens.

You would probably be much happier with the images you get by saving up for something like the EF 35mm f/2. Although it has been replaced by a newer (and more expensive) IS version, it is still available from many online retailers (at least here in the U.S.).

share|improve this answer
    
I make 0.45 * 50 to be 22.5, not 33-35 –  Matt Grum Aug 12 '13 at 8:18
    
Thanks very much for the answer Michael and the review link is very helpful. I think I'll take your advice and put my pocket money towards a 35mm :-) –  Peter Hough Aug 12 '13 at 8:37
2  
@MattGrum Unlike a sensor crop factor that is linear, magnification for screw on lenses is based on area, so 0.45x is area magnification. Focal length is linear. The √0.45 = 0.67. 0.67 X 50mm = 33.5mm. Most lenses with a focal length of 33mm are marketed as 35mm lenses. –  Michael Clark Aug 12 '13 at 9:07
    
The area magnification labeling is very interesting — I had no idea! –  mattdm Aug 12 '13 at 9:24
    
@mattdm it's misleading more than anything, since teleconverters are always specified in terms of focal length, not area. Imagine if Canon one day started calling all of their 1.4x TCs "2x" and their 2x "4x"... –  Matt Grum Aug 12 '13 at 10:26
show 1 more comment

Using a screw on wide converter with a fast lens will result in a poor quality image. If you need to shoot wide angle images at large apertures like f/1.8 then your options are limited to something like the Canon 28mm f/1.8 Sigma 30 f/1.4 both of which are around £350.

Alternatively upgrading your camera to the original 5D would cost a little more (~£450) but would act like a 0.4x wide converter that improves  image quality!

share|improve this answer
    
Thanks for your answer Matt, nice point about the 5D. I better get saving :-) –  Peter Hough Aug 12 '13 at 17:53
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.