I received to lenses recently for evaluation (from a dealer who was kind enough to let me do that!). One is a 150mm f/2.8, and the other is a 240mm f/4.5. They are longer than a normal lens for medium format (normal being about 80mm focal length), but not really L O N G for wildlife. But they came with a 2x extender, giving me 300mm and 480mm, both of which are suitable for wildlife.
This photo was taken at 480mm from about 5 feet away from our feeder:
This was about a hundred images into learning how to use such long, heavy lenses.
Here is a photo taken earlier, as I was figuring out how to use these lenses. It was taken without the 2x extender, at 240mm, and from further away:
A number of things went right and wrong here:
I didn’t use settings that would freeze the bird’s motions.
I didn’t have a useful focus setting, although it’s close—but this deep focus was part of why I couldn’t freeze motion.
The lens wasn’t long enough for how far away I was; even blown up, the details are not as good as I would like them to be.
The exposure has enough light to register details clearly
Not shown, but experienced: the focus on the camera was not working well hand-held. It is somewhat slow because the lens has really huge chunks of glass in it. It would hunt as my hands could not hold the camera steady enough for a full focus. About ever tenth image was focused the way I wanted it to be.
That first image was the result of taking images like the one above, and gradually figuring out what I need to have to make good pictures with this hardware. Here are the changes I made over the course of the several-hour session:
I got out my monopod, and mounted the camera on it. This took the weight, and I could concentrate on pointing the camera and operating the controls.
I added the 2x extender, to double my focal length
I did long sessions with each lens, instead of juggling back and forth, so I could learn the strengths and weaknesses of each.
I made subtle changes to my focus settings, so that I was more like to get to a good focus. Combined with the steadiness of the monopod, this allowed me to get about 75% of the images in proper focus. A big improvement, but still a fair number of lost images.
Having spent a good part of the day just learning how to use the lenses, it took several more days and several more sessions to actually get comfortable with them. I gradually reached for the right controls at the right time, and then it was time to try to decide between them. Here is what I had learned along the way over the course of about 5 days:
The 150mm lens, without extender, was a reasonably flexible lens. It was able to focus handheld if I was careful. (It would focus correctly about half the time.) It is a fast lens, so I had a lot of flexibility in choosing my depth of field. I could focus just on eyes, or get an entire face or bird in focus by changing the aperture.
The 150mm lens with the extender was a reasonable wildlife lens. The extender doesn’t allow automated focus, so I had to figure out how to set up to focus on the fly. The monopod was essential; I could not focus well without it.
Both lenses had better contrast without the extender. Contrast contributes to one’s sense of sharpness, even if it doesn’t affect literal sharpness directly. So for a few days, I was certain (but wrong) that the extender images were not really better. I had to work harder than I had expected to master technique in order to focus at long focal lengths manually, but in the end, once I could control focus, I finally saw the value of the longer focal lengths. I can also add in some contrast during processing afterwards.
The 240mm lens, with extender, was truly a difficult setup to master. Things began to become more useful for me after a long, four-hour session with just that setup. I’m glad I wasn’t using film; I took 196 images before I could say that I had enough skills to appreciate what the combination could do. Perseverance is not just for politics. :)
That said, I felt that budget-wise, if I could decide on keeping either the 150mm lens or the 240mm lens, I would. But in the end, the bare 150mm is really flexible handheld, and the 240mm is not. Similarly, with extender, the 240mm lens really is a lot more capable of capturing details than the 150mm. So it was a difficult decision about whether to keep one or the other; keeping either one would rule out important things I like to do with the other.
Part three: the evidence.