Houston Zoo with legacy tele lens

To finalize our long Thanksgiving weekend, the family decided to visit the Houston Zoo today. A great opportunity to practice my skills at manual focusing and the manual settings on the Olympus OMD-EM5 camera.

So, I decided to take my 75-200mm Minolta lens along. I have owned it for ages and used many many moons ago on my Minolta X-300. I had never taken it out on my Olympus mirrorless camera, so I though I would give it a swing.

My plan was to adjust to ISO 3200 for indoor shots in aquarium and terrarium areas, and to shoot low ISO outside (this almost always worked, except when I forgot a few times to switch back to low ISO when outside).

There were two principal challenges for me today:

1. Depth of Field (and with that: focus)

The inside shots were all taken at f4.5 and ISO3200. At that aperture the lens has quite a shallow DoF. The experienced photographer knows that; to me it was new and somewhat unexpected. Looking up these values tonight at my handy DoF calculator phone app, I learn that at 200mm and f4.5 I have a DoF of only 0.27cm (0.11″) at a distance of 1m (3 feet). At the widest focal setting of 75mm the lens has a DoF of 2.22cm (0.87″). Most of my inside shots were probably in-between the two focal lengths. In comparison, my Rokkor 50mm lens at f1.4 and same distance has about the same DoF as the tele lens at f4.5 at 75mm. Knowing this now, it is no wonder that I had trouble focusing that heavy piece of glass in the reptile and insect areas at low light and generally slow shutter speeds. This gives good explanation to the slivers of focus in most of the inspect and reptile pictures.

My choices would have been to increase the ISO setting (or to carry a tripod). Higher ISO was not an option due to decreased picture quality – personally I find that ISO 3200 is border line acceptable for viewing on larger screens. If I would do it over again, I’d probably try a few shots with ISO6400 and f5.6, although bringing a tripod may be the ultimate solution to this.

2. Shooting through fences

The classical zoo challenge: How to get rid of those fence lines. Well, first some autofocus cameras will have trouble not focusing on the fence in the foreground. So manual focus is the choice here. I was shooting manual already due to the legacy lens.

Getting close to the fence was not an option; the barriers in front of the fence prevented me to get closer and sneak a peak through the fence openings (or to just decrease the distance between glass and fence and thus throw it out of focus).

Using a large aperture will give a shallower DoF as discussed above and throw the fence out of focus, so shooting at max aperture (in my case today f4.5) was my option today.

The distance of the object from the fence will help with making the fence disappears. The further it is away, the more the fence will be thrown out of focus and eventually disappear. Waiting for that to happen today was not an option since my family kept moving. Animals that I kindly asked to move, were not obedient for some reason today. So fence has become part of my composition.

Thanks for visiting and reading. Please make sure to check out the pictures in my SmugMug gallery. Buy some of them too 🙂