After Scott asked the question about how / if the Sigma 500/4.5 works with TCs I thought I'd run a few tests for myself to see what the IQ was like from various combinations. I included the Sigma 120-300/2.8 because this is my 'Dawn & Dusk' lens at f2.8 as well as the one I took on vacation (along with TCs) to give me 120mm - 600mm.
Notes
All shots were taken AS I WOULD TAKE THEM IN THE FIELD. This is not a highly scientific method but a real life scenario which I prefer as other variables, that are relevant when actually birding, come into play. So no tripod and no Live View and no constant ISO as I use Auto ISO, the results are then, for me at least, more representative of real life since this is what would actually happen when birding, no constant ISO 100 and low shutter speeds. You can estimate yourself how much impact the ISO has on sharpness.
Of course this then means the only constants were my postion, f8, 1/1250, D800, Fine jpgs, and taken on a monopod using Long Lens technique (foot against base of monopod, left hand on top of the lens, gentle press against my forehead and a squeezed shutter press on slow exhale - when I see the target is stable in the VF) which is how I shoot 90% of the time in the field (except I shoot RAW but didn't think it necessary here). I took 2/3 shots at each target with each combo and picked the sharpest in each case. The targets are normal sized A4 magazines so you can easily estimate text size.
On the computer I took snapshots from the displays in Photo Mechanic using Skitch, labelled and then dragged to jpgs to SmugMug. I noticed a definite decrease in sharpness (say 10-15%) in the Skitch snapshots from the screen display but since this is a constant I don't find that an issue for comparative purposes since I'm not measuring the definitive sharpness. However viewers should realise that the actual shots taken are much sharper than those displayed here. No Sharpening or any form of PP was applied. These are SOOC and sharpening in LR4/5, PS, A3 etc would render much sharper photos.
I will make a series of posts, each post will have 6 shots, a different combination each time . All are 100% Crops of shots taken at 5.5m, 10m, 15m, 20m, 25m and 50m.
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Sigma 500/4.5 + Kenko 300 Tele Pro DGX x1.4 (700mm)
I am surprised at this first shot at 5.5M (MFD) - I would have expected the bare 500mm to be much sharper (as I know it is) and can only assume this is User Error.
binary visions wrote:
I think that first batch must be out of focus? I have trouble believing that difference between the two 1.4x TCs is that drastic.
Across all 15 -18 shots in the series ? It's not difficult to see when they are in focus through the D800's superb VF. These were the best ones of the series
Note that these are 100% crops and as mentioned above the screen shots reduced the sharpness further for all of the series. No PP or sharpening of any kind.
If that's the case, then I'd say that the Kenko 1.4x TC simply blows, at least when using it with this lens
That's pretty much the conclusion I have come to, for one reason or another the Kenko doesn't like the 500, but works very well on the 120-300. Never mind, the Nikon TC looks great !!
You should try the Sigma TCs on your 120-300. I found them superior to Nikon's and based on your shots I think you would as well. The AF speed is improved as well.
I still didn't try my TC's on the Sigma 120-300 OS. After seeing your tests, I'll definitely give it a try. I have tested the Sigma 1.4 with good results, never tried a Nikkor (I have a 1.4, 1.7 and 2.0, but didn't know they were compatible) or my Kenko 2.0. Thanks for posting this.
rd4tile wrote:
You should try the Sigma TCs on your 120-300. I found them superior to Nikon's and based on your shots I think you would as well. The AF speed is improved as well.
Thanks. I found the AF, when used with the Nikon TC on the 120-300, really lacking, very tough to actually find focus at all. The test above with the x2.0 is indeed the Sigma TC, I like it, a lot and this didn't have any issue at all.
gugs wrote:
I still didn't try my TC's on the Sigma 120-300 OS. After seeing your tests, I'll definitely give it a try. I have tested the Sigma 1.4 with good results, never tried a Nikkor (I have a 1.4, 1.7 and 2.0, but didn't know they were compatible) or my Kenko 2.0. Thanks for posting this.
Guy
Glad it inspired you to have a go Guy. The Nikkors have to have a lug filed off before they will fit (Google it - lots of instruction on how to make this simple, 10 mins, adjustment). The adaptation does not affect the TC, or it's use on Nikon lenses, in the slightest.
Thanks for doing this. Very interesting! I think the straight lens 1st image must have been a bit of user error as you stated. Otherwise, looks like the nikon tcs are significantly better than the kenos at least on the 500.
Thanks for doing this. Very interesting! I think the straight lens 1st image must have been a bit of user error as you stated. Otherwise, looks like the nikon tcs are significantly better than the kenos at least on the 500.
I use Sigma 120-300 with 1.4 and 2.0 SIGMA EX TCs at all times, I find the image quality very good for such a strong teleconverter (the 2x).
The 1.4x get amazing quality.
The speed of the AF is ok, but the accuracy on the 2x drops a bit. 1.4x is great.
The IQ with both the sigma TCs is top notch, it's just the AF speed/accuracy where the Nikon 300 and 200-400 pull away. If the limiter on the new model cleans that up it's going to be a much bigger player like the 35 f1.4. I liked that lens a lot but in the end went for the weight/handling of the new 80-400.