Posts Tagged ‘lens’

Zenitar 16mm Fisheye on 5Dmk2 – First Impressions

// February 15th, 2010 // 1 Comment » // Photography

I shoot most of my photos with wide angle lenses, so it was inevitable that I’d eventually buy a fisheye.

Zenitar 15mm fisheye photo with Canon 5Dmk2

Choosing

Given that ultrawide distortion is an easy thing to overuse though, I was looking for something in the £100-150 sweet spot – good enough to bother using, cheap enough to bother buying. Sigma and Canon models all come in over £400, so they were instantly out. That leaves two real contendors, with quite different characteristics:

  1. Zenitar 16mm f2.8 – 180 degrees corner to corner on a full frame body like the 5Dmk2, but useless on a crop sensor body
  2. Pelang 8mm f3.5 – projects a full circle on a full frame (ie. a circle in the middle of the exposure, with black all around)

As I have a full frame body, the 15mm was the obvious choice – it produces normal rectangular photos but with just enough distortion on the edges to be interesting. I am pretty certain that whilst the 8mm circle look can be cool, it would also get a lot less use than the more subtle 15mm.

Zenitar 15mm fisheye photo with Canon 5Dmk2

Purchasing

I purchased my Zenitar for about £125 from MoscowPhoto on eBay. It arrived in under 2 weeks – a week faster than they suggested it would take.
The factory ships this lens with an old M42 mount, which usually requires an adapter but MoscowPhoto had fitted an EOS mount – this works perfectly and saves some hassle.

Zenitar 15mm fisheye photo with Canon 5Dmk2

Quality

The lens looks very 70s, and it’s relatively lightweight, but for the money build quality is fine.

Zenitar 15mm fisheye photo with Canon 5Dmk2

Picture quality is impressive for the money, as long as the lens is kept stopped down to f11 or f22. With such an enormous field of view that’s sensible anyway, as it would be hard to keep everything in focus at a wider aperture. There is a little vignetting, and in two of the four corners it is impossible to avoid small triangles of black, but it isn’t that noticable and can usually be hidden by the composition.

Zenitar 15mm fisheye photo with Canon 5Dmk2

I don’t have the skills or the inclination to do any formal testing of the lens, but you can find my first batch of experiments on Picasa if you’d like to look. They were shot as S-RAW2, tidied a little in Lightroom and then shrunk to 1600px for Picasa, so not directly as the camera shot them, but a fair representation.

Zenitar 15mm fisheye photo with Canon 5Dmk2

My subjective opinion is that at f11 and above the field was sharp enough to make me happy shooting handheld, a tripod would no doubt help – at which point the key issue for sharpness would be focussing, hard to do across the whole frame. There is noticable chromatic abberation, but it’s a fisheye so I won’t lose sleep over it. Colour saturation is disappointing compared to good glass, with colours coming out quite flat, but you can compensate in RAW and for an occasional use trick lens I don’t think it’s an issue.

Zenitar 15mm fisheye photo with Canon 5Dmk2

Shooting Tips

Using such a narrow aperture obviously does make it hard to use the lens indoors. I found it could be used handheld in a dark room at ISO 2500-3200, which after some judicious editing in Lightroom produced acceptable pictures – I doubt you could use them as professional stock photos, but they’d be acceptable for small prints, web use etc. Your mileage with other bodies will vary, of course – the 5Dmk2 is spectacularly good at high ISO, so they work well together in this respect.

Zenitar 15mm fisheye photo with Canon 5Dmk2

In good light, handheld shooting was easy – remembering to manually focus was the only real issue, and was easiest done by guesstimating using the distance markings on the dial. Speaking of manual dials, it’s worth noting that everything will have to be done manually with this lens – the camera cannot read the Aperture you have manually selected, so you have to work in Manual or Tv mode and do some test shots whenever the light changes. In practice this really isn’t challenging, and doesn’t require virtuoso knowledge of light metering. Obviously shooting RAW and using a body with good high ISO is very helpful here.

Zenitar 15mm fisheye photo with Canon 5Dmk2

Overall, I’m really pleased with this lens and think it makes a great companion to a full frame SLR. The level of distortion can be subtle or extreme depending on composition and distance from subject, and works particularly well if you avoid aligning with strong horizontals and verticals. That said, it will take me a while to work out what sort of compositions it can usefully be used for, but it is light enough that you can carry it round just in case whatever the trip.

If you have a crop sensor body, however, you’ll need to look elsewhere…

Angles of View and Crop Factors

// February 5th, 2010 // 1 Comment » // Photography

Here are some more diagrams I drew to try and understand photography, specifically to understand crop factors and lens lengths.

Sensor Crop Factors

Every camera has a rectangular sensor which captures light. A “full frame” sensor is the same size as an old film negative – 35mm from bottom left to top right corner. Expensive SLRs use full frame sensors, but cheaper ones (such as any Canon in the x0D, xx0D and x000D ranges) use smaller sensors. The size of the sensor is described as its crop factor.

This diagram demonstrates the common crop factors found in digital SLRs (click to enlarge):

This explains why a larger crop factor will reduce vignetting (the darkening around the corners of a photo):

Note that we are talking here about conventional lenses designed for full frame cameras. Most manufacturers now also produce lenses which only work on crop factor sensors, such as Canon’s EF-S lens. These project a circle which does not reach the edge of a full frame sensor; understandably, these will vignette worse than the equivalent length lens designed for a full frame sensor.

Camera Lens Angles of View

The focal length of a lens is the number, quoted in mm, which indicates how close or far away things will look through it. This can be considered as an ‘angle of view’ – a larger focal length will produce a smaller angle of view – and a closer image. Think of it as the angle from the lens to the left edge across to the right edge of the frame.

Angles of view for a “full frame” sensor (click to enlarge):

In contrast, here are the angles of view for a 1.6x crop sensor:

For easier comparison, here they are side by side: