Canon 15 85 vs Canon 24 105 l

Canon EF 15 85mm f/3.5-f/5.6 vs Canon EF 24 105 f/4 is l

Canon 15 85 vs Canon 24 105

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Can check my reviews about both lenses, see at below links, note that I have a 24-105 and has much more time with it:

Compatibility:

The Canon 24-105 is is a full frame lens, can be used all kinds of SLR cameras, while the 15-85 is only compatible with Aps-C (smaller sensored) cameras. Canon don’t like the idea to use the 15-85 on FF, this way it is not even possible to mount on it, unless we cut the back part of the lens. This is an advantage if we want to change for Full frame in case of the 24 105 we don’t need to change the lens. In this article I speak about to use both lenses on Aps-C sensor sized (20d,30d,40d,50d,60d,7d 300d,400d,500d,550d,600d,650d,700d,100d) cameras.

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Focal length:

Perhaps this is the biggest difference between the two lens. The Canon 15-85mm is lot wider than the Canon 24-105mm. In fact the 15mm on Aps-C cameras are the same as the 24mm on Full frame cameras. If we speak about one lens solution the 15-85mm is lot more useful. I use my lenses at this focal length mostly the widest settings. Both lens can be used for portraits, the difference between 85mm and 105mm is not very significant in reality, one need to make perhaps one step further. If we have an Ultra wide angle lens, perhaps the 24-105 works as well as a general purpose lens.

Optical quality:

Both lens are very good compare to the relatively wide zoom range. According to me the 15-85 is sharper(especially in the center), than the 24-105. The 24 105 is better in the corners. At the long end the 15 85 is better.
At the wide end the Canon 15-85 is more prone to flare, has strong vignetting wide open, while the 24-105 gives more consistent results. The 24-105 is prone to flare as well at least the earlier copies. The 15 85 gives more dark saturated and contrasty images, while the 24 105 makes more light images. Between the two who like which is a personal decision. I like better the 15 85 colour/contrast rendition.

Specifications

Item	Canon 24-105 f/4L is	Canon 15-85 f/3.5 – 5.6 is
Mount:	Canon EF	Canon EF-s
Filter size:	77 mm	72 mm
Lens elements / groups:	18 / 13	17 / 12
Exotic Lens elements:	1 Super UD and 3 aspherical	1 UD and 3 aspherical
Weight:	670g ( 23.63 oz. )	575 g ( 20.28 oz. )
Dimensions:	83 x 107 mm ( 3.27 x 4.21 ” )	82 x 88 / 108 mm ( 3.22 x 3.47 ” )
Close focus distance:	45 cm ( 17.72 “)	35 cm ( 13.78 “)
Autofocus:	USM ring-type ultrasonic	USM ring-type ultrasonic
Stabilizer:	yes	yes
Switches:	Manual focus autofocus, stabilizer on-off	Manual focus autofocus, stabilizer on-off
Lens Mount:	Metal	Metal
Format:	Full frame	Aps-C
Magnification:	0.23 x	0.21 x
Reproduction ratio:	1 : 4	1 : 5
Aperture blades:	8	7
Distance scale:	yes	yes
Manual focus override:	yes	yes
Focal length:	24 – 105mm	15 – 85mm
Max Aperture:	constant f/4	f/3.5-f/5.6
Min Aperture:	constant f/22	f/22-f/36
Angle of view:	84° – 23° 20′ on Full frame / 50°12′ – 12°12′	84° 30′ – 18° 25′
FTM (Manual focus override):	yes	yes
Focus limiter:	No	No
Tripod mount ring:	No	No
Tilt / shift:	No	No

Brightness

The 24 105 has a constant f4 aperture throughout the range, while the 15 85mm has f/3.5-f/5.6 aperture. This means that the real difference is that at the long end the Canon 24 105 is is one f stop better(faster). At the wide end the Canon 15-85 mm has a very little advantage f/3.5-vs f/4. Both lenses has is function, which helps in landscapes in low light situations.

Built quality

The 24 105 is better built, but I don’t think it is waterproof, not even dust proof, seems dust can enter behind the front element even with new lenses. The Canon 24 105 is 100g heavier than the Canon 15 85mm. Both lenses has quick USM autofocus.

Other issues

The 24 105 is overexposes on my Canon 30D camera, to make pictures not too bright I need to adjust exposure with -2/3 f stops. What is important the 15-85 specially designed for Aps-C camera, while the 24-105 designed for Full frame cameras. With the 15 85 at wide angle setting also need some exposure compensation, especially if we make pictures upwards.

Macro

For Macro according to me the 15 85 is better.

Which one to choose:

I would choose the 15-85mm, because of the more useful range, lower price and better sharpness. I love the idea of having one lens on a camera most of the time (only for telephoto I need to change). The 24-105 is also a very good lens if we wants to go Full frame in the future or we happy with the 24mm wide angle. I have a 24-105 but mainly I bought it because it was cheap, and I want to test it. It is not a bad lens at all, with little post processing makes excellent pictures, but I feel the 24mm as well the f4 aperture is quite limiting on Aps-C (My choice here is the Tamron 17-50 f2.8 perhaps the 15-85 would be better, mainly because of the USM focusing, and wider – and longer end, but I am fine with the Tamron)