Pascal Photography Studio

Zoom lens, what’s that and what does it do?

As a photographer I get a whole lot of questions about a whole lot of photography related things. Some are easy to answer others need to be demonstrated. This one needs to be demonstrated…

I will not go into great technical details, however understand that a zoom lens usually allows for more than one “ZOOM” factor and it has moving glass in addition to focus. In fact it is usually safe to assume that the further away the glass elements are, the longer the lens is, the higher the zoom factor.

So what do we mean by zoom factor? It is the magnification that a lens can produce in relation to the human eye. In photography, it is generally accepted that a 1x zoom factor is equal to a 50mm lens on a 35mm film/digital format camera, I am not going into more details than this as it is not relevant to this post. So assuming that 50mm is 1x what would be 400mm ?

The equation is:

In a Canon EOS 5D the answer would be (400×1)/50 or 8x magnification. However with a crop sensor camera such as the Canon 7D, it would be (400×1.6)/50 and thus would result in a 12.8 magnification. But what about a 16mm wide angle lens? Well (16×1.6)/50 results in a 0.512 magnification which is a theorical negative magnification. So what are the actual result in a photo? Here are a few photos of commonly used zoom factors to illustrate, all taken at the same place with a Canon EOS 7D with a 1.6 crop factor.

16 mm (0.51x)	24 mm (0.77x)	35 mm (1.12x)	50 mm (1.60x)
70mm (2.24x)	85 mm (2.72x)	100 mm (3.20x)	135 mm (4.32x)
150mm (4.80x)	200 mm (6.40x)	300mm (9.60x)	400 mm (12.8x)
500 mm (16x)	600 mm (19.2x)	700 mm (22.4)	800 mm (25.6x)

Living with a Canon 100-400mm f/4.5-5.6 IS L lens in the wild.

Whether I like it or not, I have made a conscious educated choice the day I decided to by my 100-400mm zoom, I have made my bed and I have to live with it. But how well am I living with it?

After 11 days and some 3500 photos done with my 2 lenses, the other being a Canon 24-70mm f/2.4 L, I thought I’d report on the experience.

First if you are going to use a zoom lens for wildlife a few setting are going to be required, either put your camera on sport or set it to centre auto focus, ISO 400/800, it’s highest f-stop (4.5 to 5.6 in this case) and in continuous shooting, this is important as most wildlife will not wait for you to setup your camera or to have the perfect frame. Most wildlife photographers end up cropping their photos to re-frame anyways. I admit that though I knew about all this the day I got to the park I was so excited I forgot to do the settings… It cost me a lot of bad and unusable photos.

Next, what of the Image Stabilizer? I tried both with and without to be perfectly honest as long as you are getting a speed above 1/250 of a second leave it on, just remember that IS does not compensate for the subjects movement, it only compensates for camera shake. So, if your are like me and forget to change your settings, movement blur of the subject will be your punishment, see leopard’s paws and legs bellow? 

The IS was on, the camera told me the the photo could be taken but at ISO100, 1/100 of a second, f/4.5 I got motion blur, so the IS was a problem in this case as it allowed me to take a photograph that did not represent what I wanted. I subsequently raised the ISO to 400 and the results were quiet different. This in flight Ground Hornbill was taken with far less light the IS was on with the settings at ISO400, 1/640 of a second, f/9.0 and has very little unwanted movement blur.

So if you follow some simple principals it is possible to catch wildlife action without too much grief.

What really amazed me about the lens was the image quality and focusing speed, my Sigma never game me those qualities. The drawback, the 1.3kg added to the extended body, it can get tiring at times but a bean bag or window mount solves that problem.

Finally, the big question is whether I can live with the lens or if I wasted my money, I can assure you that I did not waste a cent, though I had to get accustomed to the lens’ character I am very impressed with the results. look at he hippo head bellow and I could never had shot this photograph of a crocodile suddenly turning away from a hippo at a rather high speed and at a distance without it, the quality of the photographs speaks for itself. My only regret… I would love to have the Canon EF 400mm f2.8 L II IS USM but the price is rather prohibitive though f/2.8 would be handy.

Focal 400mm, ISO 100, 1/400, f/7.1

Focal 400mm, ISO 100, 1/400, f/7.1

Canon 24-70mm f/2.8 L – First impressions.

It’s Wednesday and as always it’s a photography Wednesday.

I finally got hold of the infamous Canon 24-70mm f/2.8 L lens, let me say that it was a mission on it’s own, there must be a serious shortage of these lenses in South Africa. Here is are first impressions.

I can really understand why journalists love it, as an action and low light photography lens it just blows my mind. Though a realistic 38-112mm on my Canon EOS 400D it has the range I was looking for plus MACRO facilities. Able to focus at 30cm from the subject and getting the shot every time, it just is incredible.

Enough raving, the truth of the mater is in the results. I have not had the chance to put it in an action situation yet but MACRO and general photography have been tried. The first comment I have to give is that the lens is fidgety, not in a bad way but compared to the kit or 100-400mm f/4 IS L you will need to get used to it, it takes more work and a lot more interventions, the days of point and shot are nearly over. The flip side is the implacable colour reproduction. I always wandered how my wife’s little Canon PowerShot A570 IS got better colour reproduction than my Canon EOS 400D ever did, until now. This lens changed my mind about my Canon EOS 400D across the board. Additionally, the results are as sharp as a Japanese samurai sword, making is a very impressive walk around lens.

Playing with the depth of field is a joy as seen here bellow:

68mm,1/8 Sec,f/10.0, ISO 100	68mm,1/100 Sec,f/2.8, ISO 100
58mm,1/80 Sec,f/3.2, ISO 100	58mm,1/100 Sec,f/3.2, ISO 100

MACRO photography is just as easy as seen in this Ice-cream and Cake here:

70mm,1/100 Sec,f/3.5, ISO 10

Needless to say that so far I am rather impressed.

Next is the field test on wide angle, low light and action photography.

Edited typo: f/2.4 to f/2.8