Photography Musings by Dave: A Little Experiment

700mm, 1/400, f/8, ISO 200, Handheld

Somebody asked me on the Birding Ohio FB page the other day if the 200-500mm lens was adequate most of the time in relation to this image. Then he mentioned he sees a lot of people that want the 60x and 80x cameras that we can't get in a DSLR. Here was my answer,

"I think regardless of how many mm one has we always want more when shooting birds. Sometimes I pair the lens with my Nikon D7000 which gives the 35mm equivalent of 750mm fov but I prefer the D750 so much more that maybe that's my answer to you. I make the 500mm be adequate. And sometimes when I have to have more I'll pair the lens with the TC-14E II which gives me 700mm on the full-frame camera. About those 60 and 80x cameras, they generally have a smaller sensor which can start eating into image quality pretty quickly unless one is very careful about its use. That's about all I can say about those, though, because I have no practical experience with them. I hope this helps."

He replied back saying he uses a Panasonic Z1000 the most but then added, "I think you nailed it with, "I make it be adequate." So many people just keep after the next great thing and forget about the basics of quality."

1050mm, 1/400, f/11, ISO 560, Tripod

I assume by, "the next great thing", he was referring to the all-in-one super zooms. Anyway, that got me to thinking about the different ways to gain more reach with what I've got which was implied in my response, "I make it be adequate" and how effective it is. Or in other words, can I retain acceptable image quality by employing methods that extend the reach of my current setup?

700mm, 1/400, f/8, ISO 180, Handheld

Here's what I did: I used the Nikon D750 + Nikkor 200-500 f/5.6e @ 500mm + TC-14E II + 700mm and then selected the in-camera 1.5 Image Area = 1050mm. Now, I've used this lens in conjunction with the TC on the D750 before which gives 700mm but this is the first time I've used that combination with the 1.5 crop that the D750 allows (it also allows for a 1.2 crop). Image size with the 1.5 crop selected gives approximately a 10MP image. Yes, I know I can shoot the full frame and crop to the same dimensions and end up with the same image size as I can by selecting the 1.5 in-camera crop but this is what experimenting is all about, right? Trying something new and different to see how it works out.

1050mm, 1/400, f/11, ISO 100, Tripod

Well, one evening after work I shot some birds in our backyard tree at 700mm and the next evening I went to local reserve and shot birds, frogs, and snakes. Other images shot at 700mm were done this last weekend. Most of these were shot using a tripod but a couple were handheld. I'll add that I use the Kirk lens collar and their lens support (LS-2) with it. After comparing images on the iMac Retina 27" screen I can definitely see a difference where when I shot using the full frame at 700mm the images are sharper than when I employed the 1.5 in-camera crop that took me 1050mm. However, for some images I inadvertently had backed off the lens just slightly without knowing it until viewed in Lightroom where I saw the focal length mentioned at 975mm instead of 1050mm. In either case, the sharpness issue remained. I'll note, too, that I used an aperture of f/11 in some of these which is a first. I usually don't intentionaly go that high, so this is something else to explore a little more. In other words, f/11 vs f/8 for instance. And, yes, the D750 continued to autofocus with this lens at f/11 using the central focus point. That was a very pleasant surprise to discover.

975mm, 1/200, f/11, ISO 180, Tripod

In some of those cases I was able to make them look as sharp as the 700mm images in post but in others it just didn't work without looking obvious. I don't expect the difference will be seen at the size presented here so you'll have to take my word for it. And, this was a one-time comparison, days apart, shooting different subjects at different distances in different light. I think its worth repeating but shooting the same subject in the same light at the same time if possible. The only setting to be changed to make it happen is selecting/deselecting the in-camera 1.5 crop. One more thing to note is that on the D750 when using the in-camera crop what we see through the viewfinder is only an outline of the cropped area with the view outside that area still visible. That makes for a tricky situation when composing to remain cognizant to stay within that outline which is tough to do, especially when the subject is moving. So, I really don't see myself using that mode often since cropping in post will produce the same effect.