With the GM lenses that use these particular TC’s I have had zero problems with CA (kudos to Sony - they are very well corrected bits of glass indeed).
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dcstep
Senior Member
CA is subject-related, so most subjects don't cause a problem. I'll dig around in my rejects to show CA with a GM lens. It DOES happen and the teleconverters can aggravate it. I think it's "well controlled", but not totally eliminated. If I don't find one tonight, I'll try to find a shiny subject that'll exhibit it with one of my very expensive, but not perfect, lenses.
Tristimulus
Veteran Member
The basic problem is the lens - longitudinal and literally chromatic aberration is a lens issue. That CA is more or less visible under certain conditions is another matter.
To tease out chromatic aberration just misfocus the lens ever so slightly on shiny objects, branches against a bright sky, or find some dark and light transitions. Focus too far away and you get red or purple halos, too close and you get green or blue halos depending upon how the lens is corrected.
No lens is perfect when it comes to CA but the long Sony lenses are shining here, they are damn good - very little CA - with or without converters.
The 1.4x converter has a very solid reputation.
The 2.0x converters has earned a not so good reputation but mainly because:
- bad testing (like hand holding and drawing quick conclusions)
- vibrations blurring the image (800 mm or 1200 mm focal lenghts are super demanding)
- atmospheric air currents (often misinterpreted as faulty optics)
When properly tested the 2.0x converter is very good, not so if the test is bad... ;-)
The real problem with the 2X is not so much the sharpness issue (it's actually very sharp when it is used properly) but rather the fact that it loses two full stops of light.
(eg. with the 100-400 GM this typically means f11)
This can give the illusion of poor sharpness when a photographer typically compensates by cranking up their ISO setting. Especially if they are trying to capture moving subjects at a reasonable shutter speed.
For this reason I think it is a bad choice in those situations.
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dcstep
Senior Member
So true, but remember, we're talking about Sony, with excellent high-ISO performance. ISO 6400, used to be consider "high ISO" with other systems, but now it's quite useable, even with a sharp teleconverter:
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Dave
good usability point. then crop mode not useful if you tracking difficult subjects.
Entropy512
Veteran Member
Even with a tripod, you need to be careful that:
The tripod is solid
There's no give/flex/tolerance in the tripod mount or L-plate
There may be use cases where aggressive handholding is more compatible with OSS than the vibrations of the camera on an insufficient tripod (when you usually should be turning OSS off...). In general, my camera seems to shake/vibrate at higher frequency on a tripod than when handheld. Also, pushing the shutter button is guaranteed to vibrate the camera if you're not using a remote release.
Personally I don't think a wireless release is necessary if you're very careful about your cable routing.
if the sensor is your weakest link, then the TC work well. eg if lens optically good until 80 mp, and sensor to 40mp, then 2x would make the lens effective 40mp; which works well.
if your sensor is 80mp, and your lens is 40mp, 2x using makes lens 20mp; you would getter results with no TC and just digitally cropping.
on primes, the lens can handle the 1.4 and 2x for the a7r3. for the zooms northrup tested on the a7r3; it's better to not use TC
There is a difference between indoor lab testing and real world testing. It has it's place but there are definitely shortcomings. the best would be outdoor resolution color charts in trees you're going to shoot birds in at the range you typically use; very cost prohibitive. Like someone has posted here CA plays a part. Flare control, and close vs far focal distance.
using tripod makes the testing more repeatable, but may also less applicable to real use; unless it's the same tripod you use for your actual shooting. I wouldn't assume the TC doesn't have an effect on handheld shots unless tested.
I got the files on the dollar bill testing. they are under 4mg jpegs, but I think they are uncompressed enough to get meaningful results. both the 400 and 600 prime are significantly sharper on the 2x TC on the a7r3 vs non TC cropped to same FL.
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my equipment: a7iii. NATIVE: sony 50 1.8. samyang 35 2.8. ADAPTED: sigma mc11 adapter. canon 85mm 1.8. sigma (canon) 12-24 4-5.6. canon 70-300mm f/4-5.6 is ii.
if your sensor is 80mp, and your lens is 40mp, 2x using makes lens 20mp; you would getter results with no TC and just digitally cropping.
on primes, the lens can handle the 1.4 and 2x for the a7r3. for the zooms northrup tested on the a7r3; it's better to not use TC
There is a difference between indoor lab testing and real world testing. It has it's place but there are definitely shortcomings. the best would be outdoor resolution color charts in trees you're going to shoot birds in at the range you typically use; very cost prohibitive. Like someone has posted here CA plays a part. Flare control, and close vs far focal distance.
using tripod makes the testing more repeatable, but may also less applicable to real use; unless it's the same tripod you use for your actual shooting. I wouldn't assume the TC doesn't have an effect on handheld shots unless tested.
I got the files on the dollar bill testing. they are under 4mg jpegs, but I think they are uncompressed enough to get meaningful results. both the 400 and 600 prime are significantly sharper on the 2x TC on the a7r3 vs non TC cropped to same FL.
--
my equipment: a7iii. NATIVE: sony 50 1.8. samyang 35 2.8. ADAPTED: sigma mc11 adapter. canon 85mm 1.8. sigma (canon) 12-24 4-5.6. canon 70-300mm f/4-5.6 is ii.
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PWPhotography
Forum Pro
Sorry I don't have scientific explanation but only in my own experience. I'd suggest if you have a time to do such test yourself you will find shoot from a distance with a tele lens reveal more than from a close distance on a dollar bill indoor that related to OP with TCs vs cropping. Also really to reflect the actual usage of such tele lenses. I know you shoot from all distance but how often you shoot in very close distance compared to from distance on birds for example? Really you bought 600 GM to mainly shoot bees instead of birds?
dcstep
Senior Member
LOL. Surely you jest.
I shot the bee with the 100-400mm, plus 1.4x, at high-ISO and f/16 to get DOF field beyond a mm or so. I was responding to someone's comment that high-ISO, due to loss of light from teleconverters limits their usefulness. I was reminding that Sony preforms extremely well at high-ISO.
The minimum focus distance of 15-ft with the 600/f4 makes it pretty useless as a macro lens. The 400/f2.8 is only slightly better, with a MFD of 9-ft. With the 400/f2.8, the 2.0x, plus a 25-mm extension tube, takes you from f/2.8, to f/5.6 reading and then actual around f/8 with the ET. That's quite useable, but I prefer working with the 100-400mm because of its native, short MFD. As with almost all macro shooting, getting any real DOF means raising the f-stop quite a bit, as I did in the bee example, when I raised aperture to f/16.
Shooting this morning (pelicans, terns, avocets and killdeer) all were inside 20m, using the bare 600/f4..
terryreid
Senior Member
I have found the 2x to be outstanding on my 600GM and also very good on my 200-600 at 600mm.
It was so lousy on my 70-200GM it was useless, the 100-400 GM fared better but no up to my standards so the 2x sat for well over a year.
I saw some pretty good excellent in fact 4000GM shots with the 2x but the poster said it required some sharpening in pp.
Then I saw and tried my 2x on my 600 GM and was blown away and very excited as it opens up new possibilities.
I have asked in about four posts so far why it is that the Sony 2x appears to work better as the FL gets longer and if this is inherent with converters in general. To date nobody has been able or willing to explain if this is true or not or why.
I am headed out to the zoo with my 600GM and 2x on my a7riv to see how it fares in comparison to my a7rIII and also will crank the ISO up since I have read some confusing posts on poor high ISO on the IV.
600 GM + 2x tc 1/30th second on tripod with very little sharpening
600 GM + 2x tc on tripod 1/200th of second or would have been sharper
--
-Terry
https://you pic.com/photographer/TerryRStahly/?mode=best
https://500px.com/trstahly
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Colin Franks
Senior Member
You may want to post some 200-600 with 2X images here:
https://www.fredmiranda.com/forum/topic/1612951
terryreid
Senior Member
In my tests I see a tad more noise at 1600 thru 3200 and more at iso 6400 on the IV but after pp plenty good at least at iso3200 most people would be pleased at iso 6400 also but I am very picky on my 5k monitor.
These two pics are strictly of the 600 GM + 2x tc at iso 800 on a breezy day so not the best test but I see more detail in the IV on all the sample ISO's I used. I downsampled these 50% to 4752 pixels and used Nik Define 2 noise reduction and minor pp pretty much out of camera raws downsampled with lens correction and noise reduction which was minor at iso 800 to begin with.
I do not subscribe to the too much magnification argument from what I see.
a7rIII 600 GM + 2x tc 1200mm iso 800
a7rIV 600 GM + 2x tc 1200mm iso 800
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-Terry
https://you pic.com/photographer/TerryRStahly/?mode=best
500px
dcstep
Senior Member
The eye is good and sharp, at 100%, on the squirrel. I think that the problem with the fur is due to the extremely shallow DOF at this range, with this much reach. Bokeh looks great.I have found the 2x to be outstanding on my 600GM and also very good on my 200-600 at 600mm.
It was so lousy on my 70-200GM it was useless, the 100-400 GM fared better but no up to my standards so the 2x sat for well over a year.
I saw some pretty good excellent in fact 4000GM shots with the 2x but the poster said it required some sharpening in pp.
Then I saw and tried my 2x on my 600 GM and was blown away and very excited as it opens up new possibilities.
I have asked in about four posts so far why it is that the Sony 2x appears to work better as the FL gets longer and if this is inherent with converters in general. To date nobody has been able or willing to explain if this is true or not or why.
I am headed out to the zoo with my 600GM and 2x on my a7riv to see how it fares in comparison to my a7rIII and also will crank the ISO up since I have read some confusing posts on poor high ISO on the IV.
600 GM + 2x tc 1/30th second on tripod with very little sharpening
600 GM + 2x tc on tripod 1/200th of second or would have been sharper
--
Dave
terryreid
Senior Member
I was surprised at both images the flower was only at 1/30th of a second at 1200mm and their was a slight breeze they were not totally stationary.The eye is good and sharp, at 100%, on the squirrel. I think that the problem with the fur is due to the extremely shallow DOF at this range, with this much reach. Bokeh looks great.I have found the 2x to be outstanding on my 600GM and also very good on my 200-600 at 600mm.
It was so lousy on my 70-200GM it was useless, the 100-400 GM fared better but no up to my standards so the 2x sat for well over a year.
I saw some pretty good excellent in fact 4000GM shots with the 2x but the poster said it required some sharpening in pp.
Then I saw and tried my 2x on my 600 GM and was blown away and very excited as it opens up new possibilities.
I have asked in about four posts so far why it is that the Sony 2x appears to work better as the FL gets longer and if this is inherent with converters in general. To date nobody has been able or willing to explain if this is true or not or why.
I am headed out to the zoo with my 600GM and 2x on my a7riv to see how it fares in comparison to my a7rIII and also will crank the ISO up since I have read some confusing posts on poor high ISO on the IV.
600 GM + 2x tc 1/30th second on tripod with very little sharpening
600 GM + 2x tc on tripod 1/200th of second or would have been sharper
The squirrel was only at 1/200th of a second at 1200mm. I hesitated about posting this pic because of the fur but what I wanted to get across is how sharp it is where it is sharp and that the 2x does not really degrade the images on my 200-600 G or 600 GM. I still stand by my personal experience that either Sony has made better lenses or the 2x works best at longer FL's. It is even better than the 400 GM.
It may be a little of both batter lenses and longer focal lengths.
I would love to have someone who may be able to explain this from a technical perspective rather than my own experience or why this seems to be the case.
Thanks,
--
-Terry
https://you pic.com/photographer/TerryRStahly/?mode=best
https://500px.com/trstahly
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dcstep
Senior Member
If you look at the fur that's on the same plain as the eye, it's crispy sharp. The other fur is a DOF issue, not a sharpness issue. When that close to a subject, with that much focal length, you need to consider f/16. Of course, particularly with those small pixels, that may raise other issues.
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