Why is it when photographing birds they never seem to be as close as we would want them? Go figure? LOL Because of how far they seem to stay away, often times I have found myself using a 1.4X tele-converter with either a 500mm or 600mm lens (or the longest focal length of a zoom lens) in order to eliminate or reduce cropping. In past years, I had done just that with both my Olympus and Nikon gear as well as with my then Fujifilm X-T3 and the 100-400mm f/4.5-5.6 lens. Getting it right in-camera most often results in the best image quality. That includes not having to crop.
That said, the question that arose in my mind was, "Is it better to not use the 1.4X tele-converter, photograph at 400mm and, if necessary upsize my file by 1.4X (or more) using Topaz Gigapixel or is it better to just use the 1.4X tele-converter at 560mm?"
There are trade-offs using both methods. Here are some of my thoughts about using the Fujifilm 100-400mm
lens with and without a tele-converter at maximum focal length, which is mostly
what I would use for birds and wildlife:
Not using a
tele-converter
You don’t have to buy a tele-converter therefore saving a
few hundred dollars US
400mm is a shorter focal length which allows the use of a
slower shutter speed
400mm is a shorter focal length which results in greater
depth of field at any given aperture, i.e., f/8 at 400mm gives more DOF than
f/8 at 560mm
No tele-converter means a shorter, lighter lens when
handholding
No tele-converter means a faster maximum aperture which
will allow lower ISOs and less digital noise
No tele-converter requires more cropping, if necessary, which
can result in the magnification of any digital noise present
Drawbacks of using
a tele-converter
The cost of the tele-converter as well as having to keep
up with it in your bag
There is at least a tiny bit of sharpness
(resolution also?) lost when using a tele-converter
There is magnification of any technical errors you made
such as motion blur, focus that is just a tiny bit off, etc.
Maximum aperture effectively becomes f/8 for light
gathering purposes but depth of field does not increase to f/8
560mm is harder to hand hold at any given shutter speed
560mm results in a shallower depth of field which can
result in fewer tack sharp images
560mm reduces the maximum aperture of the lens which
slows down and potentially degrades autofocus accuracy and speed
That said, using a tele-converter can effectively get you
closer to your subject and result in not having to crop or minimally crop. Less cropping gives you a better file.
There may be more considerations but you understand what I mean about pros and cons in using tele-converters. I’ve used them for years and years and I’ll
tell you that the ones manufactured today are infinitely better than the ones we
used a decade or two ago. When I mention
potential loss of sharpness and/or resolution, if you have a good combination
tele-converter and lens, it is minimal and you have to pixel peep to see any differences
in your files. I think using a good
tele-converter in the right situations is definitely a benefit.
In order to answer my question, I ran a few relatively 'unscientific' tests to better understand which is the better method with my gear. Two things I want you to remember before reading on. This is a relatively unscientific test and it is with my copy of the X-T4, my copy of the 100-400mm lens and my copy of the 1.4X tele-converter. Your camera, lens and tele-converter may give you different results and I suggest you test your own gear so you know specifically how it performs.
For example, in my experience, I've had a couple copies of Fujifilm lenses that just didn't focus well with a specific camera. In those cases, I sent the lenses back and obtained a different copy that focused and locked on perfectly. I have no idea why or why not a specific lens won't work well with a specific camera but sometimes that seems to be the case.
Since I was going to try to answer that one question, I thought I would throw in a few other variables that may affect focus, sharpness, etc. Here is how I conducted my little experiment and how I set my camera.
I attached the camera to my very large and sturdy Induro 414 series carbon fiber tripod with an Oben GH-30 gimbal head. I did not compose and lock down the gimbal as that is not how its used in the field. The gimbal head can easily swivel left and right as well as up and down to track birds and other wildlife. The camera and lens were balanced on the gimbal so there was no tendency to drift up or down.
I initially set the camera for RAW + JPEG, aperture priority, aperture set to wide open, image stabilization off, 5 fps, AF-C, second smallest single point AF, Auto ISO (minimum 1/250th shutter speed), Pro Neg Std. film simulation. Later in the experiment I changed the image stabilization on and the single AF point to the smallest Zone AF group.
I positioned a 'wild animal' test subject in the far distance so it occupied just a small portion of my frame—as would a small bird. The subject had texture in its fur, visible eyes and good contrast in coloring., in other words, something the AF system could easily lock on to and hold accurate focus. (see photo above)
Since I was testing whether or not it is better to use a 1.4X tele-converter, I also wanted to find out if it is better to turn image stabilization (IS) off or leave it on with the camera and lens mounted to my gimbal head and tripod. Finally, I wanted to ascertain if a small single AF point gave better results than using the smallest Zone focusing group of points.
 |
This is a derivative of the same file as above. It was upsized in Topaz Gigapixel to 36mp from 26mp,
then cropped to approximately 2.6mp, in other words tiny. I think it holds up very well.(click to enlarge) |
Results
I'm not going to post the data but, generally, here are my findings.
All of the files that I made with the lens set at 400mm NOT using the 1.4X tele-converter and upsized from 6240 X 4160 (normal file size) to 8736 X 5824 (a 1.4X upsize to match the files using the tele-converter) looked 'better' than the native files using the 1.4X tele-converter on the lens. I know 'better' is vague and subjective but I just think they looked sharper and more pleasing. We can thank Topaz Gigapixel for that. It does a remarkable job. Your conclusion may differ from mine as your subjective judgment is most likely a bit different.
When comparing the images made at 400mm versus the ones made at 560mm, a greater percentage of the 400mm shots (no tele-converter) were in sharp focus than ones made using the tele-converter. Without the tele-converter resulted in 83% of the image files being in very sharp focus. Using the tele-converter, the 75% of the images were in very sharp focus. Image files that were just a bit off sharp focus, but certainly usable, were not counted as being in sharp focus. If they were counted both percentages would be much higher.
In my tests, leaving image stabilization (IS) ON rendered a higher percentage of images in sharp focus than with IS off. Remember, the camera was on a tripod using a gimbal head but not locked down. I didn't test using the same setup with the camera locked down tightly.
In a bit of surprise to me, using the smallest Zone focusing group of focus points was resulted in slightly more image files in sharp focus than using a single AF point. But it was only slightly better. In my opinion, I think this result could change either way depending upon the circumstances and subject matter, background/foreground clutter, etc.
Also, I made images with and without the 1.4X tele-converter with the 100-400mm lens wide open and stopped down one stop. Stopping down the camera, in this test, did not seem to make any difference in the number of images that rendered my subject in sharp focus. You would think that the additional depth of field with the lens stopped down one stop would add a bit of 'fudge factor' and result in more images being sharp but I really didn't see a difference. That is a tribute to the quality of Fujifilm's AF system, which includes both camera and lens. You have to have both perform well, not just one or the other.
The bottom line for me is that I will most likely use my 100-400mm lens without the 1.4X tele-converter, then if necessary, upsize the file using Topaz Gigapixel if I need to crop a lot to achieve the most pleasing composition.
I don't know if this information is useful to you. My point is that don't guess about what your gear will or will not do, test it for yourself so when you are out photographing, you know exactly what you need to do and what to avoid to make the best quality images.
Interesting results. I use the Olympus 100-400 for BIF. After many positive, and many not so, experiences, my opinion is the focus settings tend to be as finicky as the birds. What works well in one scene strangely is not as good in another, possibly due to ambient light. While I am very pleased with some of my BIF photos, I would starve if I was photographing flying birds for a living. The Adobe Camera Raw Enhancement software is also very good option for upsizing images.
ReplyDeleteI remember from your previous article about a Chincoteague trip with the D850 that you had an exceptional number of in-focus images. That was my experience with the D850+500 combination using the 9 pt. setting. I have not been able to match that with the Olympus setup.