Canon EF 8-15/4L USM Fisheye Lens Review
The EF 8-15/4L is supplied with a custom removable lens hood and a custom lens cap. As with all fisheye lenses with 180 degree coverage, front mounted filters cannot be used and so a rear gel holder is used which can hold up to three gels at the same time. The lens has no image stabilization, but with a lens this wide none is required. A soft pouch is also supplied with the lens. While it will certainly keep the lens clean, it does not offer much impact resistance.
Focal Length 8 – 15 mm Aperture Maximum: f/4; Minimum: f/22 Camera Mount Type Canon EF Format Compatibility 35mm Film; Full-Frame Digital Sensor; APS-C; APS-H Angle of View 180° circular to 180° diagonal (on full frame) Minimum Focus Distance 6.2" (15.75 cm) Magnification 0.39x [1:2.56] Groups/Elements 11/14 Diaphragm Blades 7 Filter Rear mounted gel Image Stabilization None Autofocus Yes Tripod Collar None Dimensions (DxL) 3.1 × 3.7" (7.87 × 9.40 cm) Weight 1.19 lb (540 g)
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So what is a Fisheye Lens
Photographic lenses tend to come in just two “flavors”. A “normal” lens is rectilinear which means that straight lines in the subject are straight lines in the image. This is the type of lens we are all familiar with.
Fisheye lenses do not keep straight lines straight, unless those lines run through or point toward the center of the image. Lines which don’t pass through (or point awards) the center of the image appear curved and so the images has a distorted appearance.
However, rectilinear lenses also distort, just in a different way. If you look at an object near the edge of a very wide angle rectilinear lens, you will see that it is significantly stretched. The wider the lens, the more stretching you see.
On the other hand, objects near the edge of a fisheye lens image are not stretched. They are curved. This is just a different type of distortion, one that’s more noticeable to most people.
So why use a fisheye lens? Well, you cannot make a rectilinear lens with a field of view of 180 degrees. It’s optically impossible if the position of the lens and the film are fixed. You can stitch several images together to do it or you can use a lens in which the film and/or lens move during the exposure but you can’t do it in a single image. Some very wide-angle cameras even resort to using a curved film plane. This is fine for film, but making a digital version would be pretty impractical.
Also as I mentioned above, the wider the angle of view of a rectilinear lens, the more objects at the edges of the image are stretched. I think the widest rectilinear lens available for a full frame 35mm camera is still 12mm, which gives a diagonal angle of view of just 122° (horizontal 113°, vertical 90°). On the other hand, a full frame fisheye can give a 180° diagonal angle of view [around 140° horizontal) and a circular fisheye gives a 180° view diagonally, horizontally and vertically.
So if you want to capture a wide field of view (in fact a hemispheric view with a circular fisheye) and you want to do it in a single shot with a handheld camera (especially a digital camera), you need a fisheye lens.
Fisheye lenses are also often used to create abstract images or images which depend on patterns more than recognizable subjects. Sometimes this can create a fresh view of things. However used without care and vision, fisheye lenses can result in images which just look bad!
Why a fisheye zoom?
That’s what I first thought when I looked at the lens. On a full frame camera at 8mm it’s a circular fisheye producing a circular image in the center of the (full 35mm) frame. At 15mm (actually just a tad shorter than 15mm) it’s a full frame fisheye which fills the frame with a 180° diagonal field of view. At intermediate focal lengths you get black corners to the image, though you can go from around a 140° horizontal angle of view to a 180° horizontal angle of view by zooming if the dark corners don’t bother you.
However I think the more useful function of the zoom is that the lens can act as a full frame (i.e. frame filling in this context) fisheye with 180° diagonal coverage on a full frame body, an APS-H body such as one of the EOS-1D series cameras and on an APS-C crop sensor camera such as the EOS 7D, 60D or one of the digital Rebels. So anyone shooting with multiple bodies in multiple formats gets a fisheye lens that can be used on all of them. Of course the lens can still be zoomed on APS-H and APS-C bodies to give various angles of views, with and without dark corners, but you cannot get a full circular fisheye view with hemispheric coverage on anything but a full frame camera.
The EF 8-15/4L USM
Using the EF 8-15/4L USM is a little more complex than using most other EOS lenses due to the extreme wide angle of coverage. For example, on a full frame camera you can only use the lens hood at the 15mm setting. As you zoom toward shorter focal lengths, the field of view would include parts of the hood.
With an APS-H camera such as one of the EOS 1D series, you can use the hood between 15mm and about 12mm. There’s actually a mark on the focusing ring which you can line up with an “H” symbol on the lens body that shows the shortest focal length at which the hood can be used without it appearing in the shot. This also corresponds to the setting at which the image fills the frame with 180° diagonal coverage.
With an APS-C camera such as the EOS 7d, EOS 60D or one of the digital Rebel bodies, the hood can be used between 15mm and about 10mm. This time the mark on the focusing ring can be lined up with a “C” symbol on the body and that gives you a 180° diagonal field of view with no vignetting and no intrusion of the hood into the image. The is actually a “Limit” switch which when set prevents you from zooming wider than this. With the limit switch set and an APS-C body, you can zoom freely with the lens hood attached without the risk of a setting which results in vignetting.
The lens cap is quite deep rather than flat since it attaches by sliding over the hood. If you are not using the hood, you have to install it before adding the lens cap. The cap and hood can be kept together as one piece, which can then be used effectively as a bayonet fitting lens hood.
Canon note that Auto Exposure modes can be used even when shooting at the widest settings which produces a circular image in the center of the frame and leaves the corners black. However due to the extreme coverage (180° in all directions) and the resulting wide range of brightness in the image in many cases, Canon recommends using manual exposure. I didn’t really find this necessary, but it’s certainly a good idea to check the image for exposure using the histogram display when using a digital camera (as 95% of users probably will be).
The coverage at the widest 8mm setting for full frame 35mm, APS-H and APS-C are compared in the image on the right. As you can see, only full frame 35mm allows the recording of the full circular fisheye image.
Test shots taken using the EF 8-15/4L USM with both an EOS 5D (full frame) and EOS 7D (APS-C) showed the lens to be an excellent performer. Even with a circular image obtained at the 8mm setting with the EOS 5D body, good sharpness was maintained right out to almost the very edge of the image circle. Chromatic aberration was detectable in the corners of the image (or the edges of the image circle) at all settings, but that’s normal for this type of lens. Correction of CA using Canon’s DPP software (see below) was quite effective when the lens/camera was supported by the program.
On the right are three 100% crops taken from images shot with the EF 8-15/4L USM at f4, f5,6 and f8 using an EOS 5D full frame DSLR. The whole image is shown at the upper left. The crops are taken from the extreme edge of the image circle (box shown in red). The subject is a TV antenna (remember those?). As you can see, the linear elements of the antenna are sharp at all apertures. In fact there is very little change in image quality when stopping down. The blue fringe on the extreme edge of the image circle is something which all circular fisheye lenses show. Normally when printed, a hard edge is formed by cropping a circular image to exclude the border. Chromatic aberration is almost absent on the elements of the antenna, which is excellent performance. Sharpness is also very good.
A similar image sequence is shown on the right, this time with the lens set to 15mm (180° diagonal fisheye). The whole frame is shown in the upper left, with the area expanded to 100% in the crops outlined by the red box. Again the sharpness is good at all apertures, though it does improve slightly going from f4 to f8. A small amount of chromatic aberration is visible, but this can be largely corrected in DPP (see below) if you are shooting with a more recent DSLR.
Center sharpness was good at all focal lengths and apertures. Nothing to complain about here.
A reduction in vignetting was observed as the lens was stopped down, but vignetting isn’t strong and can easily be corrected using DPP or other image editing software.
Flare resistance was excellent. Even with the sun in the frame I could only see a small patch of lowered contrast due to internal reflections. Again this is excellent performance.
Canon Digital Photo Pro (DPP)
Using Canon’s DPP software the RAW images taken with the EF 8-15/4L USM can be corrected for illumination (vignetting) and chromatic aberration, as well as all the normal RAW options for color, exposure etc. Various fisheye “corrections” can also be made. For example you can convert the fisheye image into a rectilinear image by selecting the “Emphasize Linearity” option. However be aware that due to the extreme wide angle nature of the lens, a rectilinear conversion will stretch objects near the edges of the frame. This is especially noticeable if you try to linearize a shot taken at 8mm.
Note that in order to apply these additional corrections the DPP software must recognize both the camera body and lens as being supported. I found that full support was available for the EOS 7D. but that the 8-15/4L when used with an EOS 5D (original version) was not supported. That means that you can’t correct for illumination, chromatic aberration and you can’t apply fisheye conversions to the image.
Why Canon would do this, I have no idea. They could provide the options with manual control (supported lenses/cameras have built in default corrections), but they don’t. I spent 15 minutes on the phone with a Canon software specialist who confirmed that the 8-15/4L on an original EOS 5D is not supported for lens corrections. The 5D MkII is. Canon could offer no advice on how the software might be “fooled”.
Other software can be used for CA correction and fisheye remapping of course. Later versions of Photoshop, DXO and PTlens all have some capabilities in this area. Using Photoshop CS2 I was able to pretty much eliminate CA on images shot with the EF 8-15/4L USM on an EOS 5D.
The Canon EF 8-15/4L USM is a high quality lens with very good optics and a solid construction. The images obtained with it showed good contrast and good resistance to flare. Though the lens does show some chromatic aberration at the edges of the frame (and image circle), that’s very much par for the course with a fisheye lens and judicious use of the CA correction function in Canon’s DPP Raw converter software can significantly reduce CA.
Sharpness is good, especially in the center of the image, even with the lens wide open at f4 and AF is fast, silent and accurate.
Besides the ability to zoom and act as both an 8mm circular fisheye and a 15mm frame filling fisheye on a full frame 35mm camera, the EF 8-15/4L USM can act as a full frame (i.e. frame filling) fisheye with a 180° angle of view on both APS-H format cameras (EOS 1D series) and APS-C cameras (EOS 7D, 60D and digital Rebels).
Fisheye lenses aren’t for everyone, but if you have a need for one, and one that can produce professional quality images, then if you shoot with a Canon EOS system, this is the lens to get. That especially applies if you shoot multiple digital formats and want one lens that can be used on all of them.
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Examples of Fisheye Lens Images from our member’s galleries
Here are some examples of fisheye images taken by members of photo.net. These images were not taken with the Canon EF 8-15/4L USM fisheye zoom but are included here as good examples of the effective use of a fisheye lens.
The original photographers (credited on each image) own all copyrights on these images.