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Clear image zoom Sample

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Post Options Post Options   Quote Fivepin Quote  Post ReplyReply Direct Link To This Post Topic: Clear image zoom Sample
    Posted: 13 May 2015 at 01:08
Ok. I had to post this. As many of you Know I am testing my new Tokina 300 f4. Today I played with my Tamron Mx-AF MC4 and Promaster Spectrum 7 1.7. I have had excellent results with the Tamron and usually say that you cannot tell the difference when in use. The promaster not so much. You lose a little detail and there is slight CA added. I still use both quite often and the results are pretty good. However that being said on the Tokina not so much. AF works with both adapters. I was excited. Until I zoomed in 100 percent. Both adapters showed a huge loss of detail. To the point where I was not happy with any shots I took with either. The Tokina with these guys was just not sharp. So tonight I had a brilliant Idea. Try the Clear image zoom. I did some test with both adapters and the clear image zoom. I have to say the clear image zoom beat both hands down. Below find a sample that I uploaded via my facebook so quality may not hold up. But it will show my result. The first image is on the A77ii (450mm equivalent) with a 2x clear image on. so (900mm equivalent). Lighting was not great I used AF on a tripod for the test...My point is try the clear image zoom if all else fails people. I was really surprised. You get the idea from this sample but the originals are much better.



100% 1920 x 1080 crop
G.R.
 



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joel22484 View Drop Down
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Post Options Post Options   Quote joel22484 Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2015 at 20:10
Looks pretty good. Do you have a comparison shot with the tc?
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 2015 at 10:44
Yes, the results can be impressive. I'm not as surprised as you, having played around with various TC and lens combinations before. My impression is that a 20MP crop sensor will beat most of the longer telephoto lenses, most of the time, or at least be somewhere close (not true of all lenses, though). I'm tempted to add *all* telephoto zoom lenses, but I'd better not! )

TCs always degrade the image (always in contrast, usually in apparent sharpness, and often in ultimate resolution), and though the best matched 1.4x combos *may* give you some benefit in sheer resolution (though you usually need plenty of PP to get the contrast and visual sharpness back), most combos don't in my experience. Tamron made some excellent matched TCs in their adaptall days but even those struggle to improve on the digital zoom on my A58.

TCs were absolutely great on a fast lens in film days, and even in the early days of digital, but frankly most lenses and TCs cannot actually maintain a circle of confusion low enough to challenge the best crop sensors, so they can't reliably beat a digital zoom. And yes, this is one area where crop-sensor cameras beat the FF versions!

I haven't tried every possible combination, but my own trials suggest that a 2x TC will always give worse resolution (on a 20MP crop sensor) than a digital zoom, and only 1.4x are worth trying. My understanding of the issue is that on a long focus lens, the angles of incidence of the light are so small, that the slightest imperfection in either the lens or the TC causes these to diverge from where they should be; and since the TC magnifies the image, it also magnifies the error. It is already difficult to get the glass surfaces flat enough (on a microscopic scale) and accurate enough in curvature (on a large scale) to make a long telephoto give the same resolution that an equally well-designed lens of much shorter focal length will. Doubling the focal length with a TC just makes the problem worse.

There does seem to be a 'sweet spot' around 300mm, though, and plenty of people use one of these for sports/birding/etc (ie in preference to 500mm) to give the fast aperture for low light and the wide angle for close subjects, and then use a 1.4x or 1.7x TC to give the longer focal length when needed. Should I ask them whether they've tried the digital zoom instead or will you?

Though having said all this, there seem to be plenty of people using TCs on fast expensive telephotos who seem quite satisfied with their results, so possibly they know something I don't (or are they all on FF?).
Miranda F & Sensorex, Sony A58, Nex-6, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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Post Options Post Options   Quote Fivepin Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 2015 at 13:25
Miranda F. I went out again yesterday and tried the TC's in some good light. I ended up with much better results. I think the combination of really dark day and light loss from the converters made me bump the ISO up too high 1000 and I was losing detail and yet still did not have enough shutter speed for some of the shots. Thus my disappointment. On the second go round my results were acceptable. However now I know in bad conditions I can use the Clear image zoom as a replacement. I will in fact be doing some more testing to see how a TC and clear image zoom turn out when used together. I need a good sunny day for that test though...Oh the possibilities are endless.
G.R.
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 2015 at 13:48
Fivepin, I went out and did a few tests as well. The Kenko teleplus 1.4 (an old one with a dead chip inside it, rewired straight though) gave sharp results, slightly sharper than the digital zoom, but as none of my long lenses have a wide enough aperture to make AF viable at their maximum focal length, I tend not to use it very often

I recall the M42 2x TC ruined the performance of all my 300mm+ lenses, though taking half the elements out (yes!) to convert into a 1.4x was slightly better.

Of course TCs *can* work with many lenses, but I suspect you need quite an expensive lens to make a TC both workable *and* worthwhile using.

However I did find the last time I did much experimenting that the best way to get a 2x boost in focal length and maximise resolution was a 1.4x TC plus 1.4x digital zoom; this beat any of the 2x teleconverters I used, and also beat the 2x clever zoom on the A58.

Miranda F & Sensorex, Sony A58, Nex-6, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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Fivepin View Drop Down
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Post Options Post Options   Quote Fivepin Quote  Post ReplyReply Direct Link To This Post Posted: 20 May 2015 at 15:48
I have been doing more testing and yes. I also love the combination of the 1.4 converter and 1.3 on my digital zoom. To me this gives the best image sample. I have won a kenko pro 300 2x and am winning on a 1.4 kenko pro 300 on ebay. I have come to the conclusion that both of my teleconverters are mediocre at best. (tamron mc4 and promaster 1.7).
On smaller primes I like them both. (Minolta 135). On the 300 tokina and the 70 - 400...not so much. I will continue to do some testing with the new converters. I am not expecting the world with the 2x...but if it beats my Promaster1.7x (which it should). I will be happy.
G.R.
 



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Post Options Post Options   Quote Peekayoh Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2015 at 16:34
First thing I would say is that clear image zoom is simply an in camera crop and enlarge and no better than crop and enlarge in PP; worse probably seeing as it's a JPEG only option. Not saying it can't be used for the sake of convenience but I wouldn't go there for any "critical" shot.

Originally posted by Miranda F Miranda F wrote:

Yes, the results can be impressive. I'm not as surprised as you, having played around with various TC and lens combinations before. My impression is that a 20MP crop sensor will beat most of the longer telephoto lenses, most of the time, or at least be somewhere close (not true of all lenses, though). I'm tempted to add *all* telephoto zoom lenses, but I'd better not! )
Not sure what you mean by this unless you are saying that long teles can't out resolve a 20Mpix sensor; probably not what you mean.

Originally posted by Miranda F Miranda F wrote:

TCs always degrade the image (always in contrast, usually in apparent sharpness, and often in ultimate resolution), and though the best matched 1.4x combos *may* give you some benefit in sheer resolution (though you usually need plenty of PP to get the contrast and visual sharpness back), most combos don't in my experience.
A TC may degrade an image but you have to compare the result with a cropped and enlarged image without the tele and then it's a different story. In my experience, a 1.4x Tele beats the crop/enlarge image option and so does the 2x although it's debatable whether the 2x beats a crop/enlarge from the 1.4x tele. Mind I should qualify that by saying I only own and have only used OEM matched Teles i.e. Minolta 2x converter-S, Minolta 2x converter-L, Sony 1.4x and Sony 2x. I can't speak for third party and possibly inferior options.

Originally posted by Miranda F Miranda F wrote:

Tamron made some excellent matched TCs in their adaptall days but even those struggle to improve on the digital zoom on my A58.
If that's true, then they can't be all that good, can they?

Originally posted by Miranda F Miranda F wrote:

TCs were absolutely great on a fast lens in film days, and even in the early days of digital, but frankly most lenses and TCs cannot actually maintain a circle of confusion low enough to challenge the best crop sensors, so they can't reliably beat a digital zoom. And yes, this is one area where crop-sensor cameras beat the FF versions!
If I'm following your chain of thought correctly, I think you're saying that it's better to use a crop sensored camera rather than use a FF plus TC but that's an Optical rather than Digital zoom so I'm not sure I'm quite following your logic. As for the CoCs, don't forget that a crop sensor is already at a 50% disadvantage in that regard so a 1.4x TC on a FF only serves to equalise the equation somewhat, provided that each has the same number of pixels eg. a77 / a99.

Originally posted by Miranda F Miranda F wrote:

I haven't tried every possible combination, but my own trials suggest that a 2x TC will always give worse resolution (on a 20MP crop sensor) than a digital zoom, and only 1.4x are worth trying.
I think you're trying with the wrong equipment and BTW, the resolution of the sensor is immaterial. My experience tells me that when you need the extra reach, a matched tele extender (OEM) does the trick; where things get a little muddy is that a crop and enlarge from a 1.4x to 2x is not markedly different from the 2x tele result and the extra stop lost can then be an issue.

Originally posted by Miranda F Miranda F wrote:

My understanding of the issue is that on a long focus lens, the angles of incidence of the light are so small, that the slightest imperfection in either the lens or the TC causes these to diverge from where they should be; and since the TC magnifies the image, it also magnifies the error. It is already difficult to get the glass surfaces flat enough (on a microscopic scale) and accurate enough in curvature (on a large scale) to make a long telephoto give the same resolution that an equally well-designed lens of much shorter focal length will. Doubling the focal length with a TC just makes the problem worse.
I don't think there's any evidence to support this, for instance an 18/3.5 Distagon tests out on DxO to offer similar resolution to the Sony 500/4.

Originally posted by Miranda F Miranda F wrote:

There does seem to be a 'sweet spot' around 300mm, though, and plenty of people use one of these for sports/birding/etc (ie in preference to 500mm) to give the fast aperture for low light and the wide angle for close subjects, and then use a 1.4x or 1.7x TC to give the longer focal length when needed. Should I ask them whether they've tried the digital zoom instead or will you?
I don't know about any "sweet spot", it's only that a 300/2.8 is just Ok for hand holding and fast enough to allow the use of TCs whilst still offering AF.

Originally posted by Miranda F Miranda F wrote:

Though having said all this, there seem to be plenty of people using TCs on fast expensive telephotos who seem quite satisfied with their results, so possibly they know something I don't (or are they all on FF?).
Yes, I'm one of those "satisfied" users, I may or may not know something you don't but I'm not FF only, I use A99 and a77 for Aircraft/Action. The two cameras with the 300/2.8 gives me a mix of FLs between 300 and 900 (read equivalent FL where appropriate) although fast changes are an issue.

Here's a sample with the a99, 300/2.8 wide open with 1.4x tele. The image is still cropped so the 2x might have done the better job.

TYPHOON (Italian Eurofighter)


A99 * Sony 300/2.8 SSM * Sony 1.4x Tele (420mm Equivalent) * iso100 * f/4 * 1/1250th [+1EV]
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Fivepin View Drop Down
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Post Options Post Options   Quote Fivepin Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2015 at 17:11
Originally posted by Peekayoh Peekayoh wrote:

A TC may degrade an image but you have to compare the result with a cropped and enlarged image without the tele and then it's a different story. In my experience, a 1.4x Tele beats the crop/enlarge image option and so does the 2x although it's debatable whether the 2x beats a crop/enlarge from the 1.4x tele. Mind I should qualify that by saying I only own and have only used OEM matched Teles i.e. Minolta 2x converter-S, Minolta 2x converter-L, Sony 1.4x and Sony 2x. I can't speak for third party and possibly inferior options.


That is exactly the point I was making with this post. I did direct comparisons against a Tamron MC4 1.4x and a promaster spectrum 1.7x with the 300 tokina and the digital zoom easily beat both options. Not even close. On different lenses I have had good luck with those inferior teleconverters, but here this was not the case. So as a viable option One can easily use up to 1.4 clear image zoom and attain better results than the low end 3rd party TC's. I will be doing a thorough test in the upcoming weeks with a new Kenko 300 pro 1.4x and a Kenko pro 300 2x. These are highly regarded and hard to find So I am hopeful. I will also throw the two previous mentioned converters in as well as digital zoom and will post all results with 100% 1920 x 1080 views for the world to see and we will then have a definitive answer.

Until someone points out that my testing was somehow flawed or that my A99 was not good enough...or that the Kenko's are not good enough..or...or ..or

Edited by Fivepin - 22 May 2015 at 17:21
G.R.
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2015 at 18:10
In addition to the many comments posted regarding TCs, there is yet another consideration: Specific lens/TC combinations can be good matches or not-so-good matches, sometimes giving disappointing results with otherwise good optics or quite satisfying results with ordinary optics.
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Post Options Post Options   Quote Peekayoh Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2015 at 23:10
People tend to use TCs indiscriminately. The only lenses recommended by Sony for use with their Teles are the SAL500F40G2, SAL300F28G22, SAL70400G23, SAL70200G22 and SAL135F283.
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 22 May 2015 at 23:20
Originally posted by Peekayoh Peekayoh wrote:

People tend to use TCs indiscriminately.

Do they? I figure they* more likely use them in a limited range of situations with a limited range of lenses, or even with just one lens.

* They who indulge in technical discussions in web forums.
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Post Options Post Options   Quote Miranda F Quote  Post ReplyReply Direct Link To This Post Posted: 26 May 2015 at 14:33
I agree with Fivepin, and I'm sorry that my points weren't clear to Peekayoh.
To pick up just a couple of the points, if you have (say) a 6MP FF camera, then the pixel density is much lower than the A58 with its 20MP crop sensor. As a consequence, almost *any* TC will give you more resolution on the FF, but with the greater pixel density of the A58, A poor TC is quite likely to give you the same blurred image detail covering more pixels. This assumes a given lens, of course, and the mere fact that you are considering using a TC says that you can't just pick a longer lens for your FF camera to make things equal.

The greater the pixel density of the sensor, the better you are off using the digital zoom. And therefore, the higher the pixel-count on the sensor, the better a TC has to be optically to show an improvement over the digital crop/zoom. In my opinion, many of the 2x and 3x TCs designed in film days are simply not good enough for use on modern digital crop-sensor cameras (indeed, some weren't that good on film transparancies) either.

For jpeg shooters the clear-image zoom does give different results from PP crop and resize, because the jpeg compresison is done on a smaller area of the picture so the limited frequency content of the jpeg is less of an issue. That says nothing about how good the in-camera resampling is, though. Raw shooters will of course have the most freedom in PP.
Miranda F & Sensorex, Sony A58, Nex-6, Dynax 4, 5, 60, 500si/600si/700si/800si, various Sony & Minolta lenses, several Tamrons, lots of MF primes and *far* too many old film cameras . . .
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 26 May 2015 at 17:15
Originally posted by Miranda F Miranda F wrote:

For jpeg shooters the clear-image zoom does give different results from PP crop and resize, because the jpeg compresison is done on a smaller area of the picture so the limited frequency content of the jpeg is less of an issue.

I don't get what you're saying.

I know of a possible advantage of the in-camera solutions for JPEG shooters, but it's not that. The difference is that an in-camera cropping/manipulating process will involve only one lossy compression step to save the final result. Shooting a full size JPEG and then cropping/manipulating it will involve two lossy compression steps for a final JPEG file. And even that falls more into the realm of nice to know, but not necessarily an observable difference in practice as long as the quality levels are set high enough.

Edited by sybersitizen - 26 May 2015 at 17:18
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Post Options Post Options   Quote sybersitizen Quote  Post ReplyReply Direct Link To This Post Posted: 26 May 2015 at 22:04
Originally posted by Fivepin Fivepin wrote:

I will be doing a thorough test in the upcoming weeks with a new Kenko 300 pro 1.4x and a Kenko pro 300 2x. These are highly regarded and hard to find So I am hopeful.

I have those TCs and am more than pleased with them - when they're used with specific lenses and in the most advantageous way.

I will also throw the two previous mentioned converters in as well as digital zoom and will post all results with 100% 1920 x 1080 views for the world to see and we will then have a definitive answer.

Definitive for the specific lenses you test, and under the specific testing conditions.

Until someone points out that my testing was somehow flawed or that my A99 was not good enough...or that the Kenko's are not good enough..or...or ..or

It depends not just on the lens/TC combo being tested, but also on what you want a TC for, and thus what you test for.

Many people want to use a TC with their lens or lenses only at or near maximum aperture, so they only test for that and will come to conclusions based on that. Nothing wrong there, but it's not the whole story. Sometimes max aperture is not necessary or even desirable.

I just tested my Pro 300 2x in combination with my original Minolta 100/2 and 100 macro lenses. I tested with the lenses at f/5.6 rather than max aperture. (When I say f/5.6 I mean the same f/5.6 both without and with the TC, thus operating at effectively f/11 with the TC.) After all, I will at times be able to shoot at f/5.6 outdoors, so why not test it? The difference in the results is dramatic: The TC shots are far superior to non-TC shots cropped and resized... and this is with a 100mm lens, which is much less than the supposed ideal focal length range to be used with the Pro 300 series. The downside, of course, is the reduced effective aperture and the resultingly longer shutter speed required. But if maintaining image quality is a top concern, and if shooting conditions support the choice, it is a certainty that many lens/TC combinations can and will produce results that can never be matched with cropping/manipulation, either in-camera or with PP.
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