could use some help with this... - teleconverter (lenses, cameras, zoom)

[EinsteinsGhost]

Originally Posted by blueflames50

please stay on topic, it is well understood the issues of sharper image quality..now moving on if anyone has tips of use of the teleconverter to get the best shots (as this is the original question) with this combination please add to the conversation. tips such as changing the f stop...to allow more light, taking a flatter light image or such. thanks

I have a 2x TC that I use only under extreme conditions (such as photographing the moon)... as in maximizing maximum zoom. So, anything less than that, I would not use the TC.

TC will affect the aperture size dramatically, usually cutting it down in half. My 300mm zoom lens has a max aperture of f/5.6, but with 2X TC, the largest aperture I can get is f/11. This can also result in slower (auto) focus or continuous hunting. I go manual by default.

[Floyd_Davidson]

Originally Posted by EinsteinsGhost

TC will affect the aperture size dramatically, usually cutting it down in half.

The effect of a TC on aperture is exactly the same as the effect of focal length. A 1.4x TC multiplies both aperture and focal length by 1.4x, a 1.7x TC multiplies by 1.7x and a 2x multiplies by 2.0.

Decades ago Vivitar, Soligor and maybe others marketed 3x TCs too, but they were all so horrible as to be useless!

My 300mm zoom lens has a max aperture of f/5.6, but with 2X TC, the largest aperture I can get is f/11. This can also result in slower (auto) focus or continuous hunting. I go manual by default.

Nikon's AF "requires", according to the book, an aperture of at least f/5.6 to work, though at least with the pro bodies f/8 is often sufficient. I doubt that any lens is going to AF with a maximum aperture of f/11. Note that AF is not slowed by the use of a TC.

The biggest problem with a TC is trying to make silk from a sow's ear! Consumer zoom lenses are always barely on the edge of useable, due to the many compromises that are necessary to either provide wide zoom ranges (i.e., anything greater than 3x zoom) or to keep the cost low. Almost all such lenses are barely sharp enough at the ends of either the zoom range or near maximum aperture, hence multiplying the defects (chromatic aberrations and effects of astigmatism are the worst) will often make such a lens less useful with teleconverters. Obviously the higher the magnfication of the TC the bigger the problem, which is why many people recommend using 1.4x or 1.7x but not 2x TCs. To a very great degree that has to be tempered by the type of use (macro work, with close focusing and narrow apertures is less affected, for example) and the lenses used (fixed focal length lenses are usually more useful, and only the highest quality zooms are).

The bottom line is that on a typical wide to short focal length telephoto zoom, a TC is not very useful at all, while a fixed focal length 400mm f/2.8 with a good 2X TC is virtually identical optically to an 800mm f/5.6.

[blueflames50]

Einstein...."I go manual by default"....are you referring to manual focusing?? as I am manually focusing with this set up. what would you figure/guess is my max aperture with this configuration...

An Floyd....don't feed into this ....it is pretty obvious with posters on this forum who is current on photography equip. and who isn't...some info is timeless the updates and quality of equipment isn't. Thanks to those who DM and emailed starting way back when I wanted to purchase the teleconverter to work with this lens. Having seen many many examples of photo's shot with Tele's....I know what the capabilities are and quality are...

[EinsteinsGhost]

Originally Posted by Floyd_Davidson

David, have you actually ever used a decent teleconverter? Do you even own a camera that could use one, much less currently own or use a teleconverter? Do you know anything about when they are useful and when they are not?

While you addressed this to David, allow me to chime in on the subject. I would say that adding more glass to a lens will always add to the possibility of worse IQ, including sharpness no matter the quality of glass on its own. After all, and ignoring the convenience and cost aspects, would you prefer the best 500mm lens (IQ and speed) over the best 200mm lens with the best one or two TCs to get to 500 mm?


Among your examples, I see EXIF in one (the duck shot) and it answered my issue with graininess/noise. The picture was taken at a high ISO (3200), perhaps with post processing involved for sharpening. I wonder if the same shot could have been taken at 200mm (the maximum focal length of your zoom lens) at a lower ISO and cropped and compared to one with just one TC (also cropped) and to the one above.


Here is a shot of an active duck taken when the sun was barely over the horizon, with the subject being about 100 ft out, at ISO400, using Minolta 200mm/f2.8 APO HS G mounted on Sony A55, then cropped.




I could have cropped further to resolve even the feathers (but didn’t do that to keep the bubbles in frame). I could have avoided the cropping using the 2X filter I have but then, I would not have been able to use the largish aperture. A 2X TC I had in the bag would have cut the aperture in half while (mostly) eliminating the need to crop.


I limit my use of TC to shots of stationary objects with the longest zoom I have (300mm/f5.6), or the moon (which appears to move quite briskly at an effective 900mm focal length equivalent) as it guarantees a max aperture of f/11. Coincidentally, that would be the aperture for most lenses after which softness will begin to show due to refraction. Not so much an issue in landscape shots, but for details, yep.

[EinsteinsGhost]

Originally Posted by blueflames50

Einstein...."I go manual by default"....are you referring to manual focusing?? as I am manually focusing with this set up. what would you figure/guess is my max aperture with this configuration...

Yes, I apologize for not being clear, by manual I meant manual focus. Focusing is fastest the largest the aperture, and a TC will affect that. Your 1.7X on your lens will force you to a maximum aperture of f/5.0. I believe the lens you’re speaking of is a constant 2.8 across the range so I would think the TC won’t have much effect at all, except that you can’t go any wider than f/5.0 if the lighting demands it. But then, you will be getting up to 340mm zoom (before factoring in the APS-C crop factor).
On a variable aperture lens, the aperture multiplication issue of TC is of greater importance.

[Floyd_Davidson]

Originally Posted by EinsteinsGhost

I would say that adding more glass to a lens will always add to the possibility of worse IQ, including sharpness no matter the quality of glass on its own.

But saying there is a possiblity (which makes your comment virtually useless because you don't specify when there is or is not that possibility), is very different that saying "anytime you use any tele convertor - your sharpness suffers immensely", which is simply not true.

The only discussion of interest is one addressing when the possibility is a fact.

After all, and ignoring the convenience and cost aspects, would you prefer the best 500mm lens (IQ and speed) over the best 200mm lens with the best one or two TCs to get to 500 mm?

Ignoring significant aspects, such as the thousands of dollars that a good 500mm lens costs, is not sane.

I did give one example that is interesting. Compare a 400mm f/2.8mm lens and a 2x TC with an 800mm f/5.6 lens. There is just about exactly one odd difference... you can add a TC to the 800mm lens and expect to get reasonable result that are better than adding the same TC to the other combination. For use at 800mm, they are just about the same. (Actually, if a number of different TC's are tried, some will actually be better added to the 400mm+TC than when used on an 800mm lens!)

Among your examples, I see EXIF in one (the duck shot) and it answered my issue with graininess/noise. The picture was taken at a high ISO (3200), perhaps with post processing involved for sharpening. I wonder if the same shot could have been taken at 200mm (the maximum focal length of your zoom lens) at a lower ISO and cropped and compared to one with just one TC (also cropped) and to the one above.

It was taken on a lark, and I really did not expect usable results. For that reason I only shot off a few exposures, just to see what happened, and didn't make any effort at testing it. I was astounded. Regardless, I actually doubt that cropping a shot at 200mm would have been better, considering how much I cropped the 500mm shot!

And ISO 3200 isn't really high for a Nikon D3S. I set it to Auto ISO with a limit at ISO 10,000, though I sometimes allow 12,800 too.

Of course the image was post processed, and appropriately sharpened! So are JPEG images straight from the camera (though the "appropriateness" might be open to question). Read what kdog said to you about post processing in the other ongoing thread about that. He's dead on right.

Here is a shot of an active duck taken when the sun was barely over the horizon, with the subject being about 100 ft out, at ISO400, using Minolta 200mm/f2.8 APO HS G mounted on Sony A55, then cropped.
[...]
I could have cropped further to resolve even the feathers (but didn’t do that to keep the bubbles in frame). I could have avoided the cropping using the 2X filter I have but then, I would not have been able to use the largish aperture. A 2X TC I had in the bag would have cut the aperture in half while (mostly) eliminating the need to crop.

I'm not sure I see a valid point there... :-) My point was that with a really really good 70-200mm zoom (the Nikon is certainly the best 70-200mm zoom ever marketed) it is even possible to get usable images when stacking TC's. That's a bit astounding, and it most certainly demonstrates that it is absurd to claim the use of a TC always results in "immensely" impaired sharpness.

I limit my use of TC to shots of stationary objects with the longest zoom I have (300mm/f5.6), or the moon (which appears to move quite briskly at an effective 900mm focal length equivalent) as it guarantees a max aperture of f/11.

Different equipment and different types of photography present different problems and solutions. I very commonly use TC's for macro work. I very commonly use either a 1.4x or 2x TC on a variety of high quality lenses, with the mentioned 70-200mm f/2.8G VRII and the 400mm f/2.8 being the most often.

Coincidentally, that would be the aperture for most lenses after which softness will begin to show due to refraction. Not so much an issue in landscape shots, but for details, yep.

You probably meant to say diffraction; but in any case that depends more on the sensor size than on the lens, with Nikon's 1.5x cropped DX sensors showing some diffraction at f/11 and significant diffraction at f/16, but the 1.0x cropped FX sensors are the same at f/16 and f/22. Note also that HP Sharpen can virtually reverse the effects of about 1 or 2 stops of diffraction, so even with a DX camera it should not be significant until perhaps f/22 for a competent photographer.

[EinsteinsGhost]

Originally Posted by Floyd_Davidson

But saying there is a possiblity (which makes your comment virtually useless because you don't specify when there is or is not that possibility), is very different that saying "anytime you use any tele convertor - your sharpness suffers immensely", which is simply not true.

I left room for exceptions (something I am not aware of existing). And degree of effect on IQ will vary, on a lot of factors. Photography is about compromises. Which takes us to the next point…

Ignoring significant aspects, such as the thousands of dollars that a good 500mm lens costs, is not sane.

It is, if your argument is to be focused on image quality as opposed to cost. If you say “but a 500mm lens costs thousands more”, you are helping make the point opposite yours that using smaller focal length lens plus TCs is a cheaper alternative to getting similar results at a budget price as opposed to same results at a high cost. Note, similar would imply a compromise. There is a reason such focal lengths in a quality lens come at a price.

I did give one example that is interesting. Compare a 400mm f/2.8mm lens and a 2x TC with an 800mm f/5.6 lens. There is just about exactly one odd difference... you can add a TC to the 800mm lens and expect to get reasonable result that are better than adding the same TC to the other combination. For use at 800mm, they are just about the same. (Actually, if a number of different TC's are tried, some will actually be better added to the 400mm+TC than when used on an 800mm lens!)

But a 400mm lens will allow you larger aperture if necessary. And if its IQ is best between 5.6 and 8.0, and you might choose 6.3 for a particular shot. With a TC or two, your options might push you past the optimum range.

Regardless, I actually doubt that cropping a shot at 200mm would have been better, considering how much I cropped the 500mm shot!

I think you might be surprised. The only solution might be to take a good prime (say, 200mm) and take identical test shots at the optimal aperture with one and then two TCs, all cropped for identical frame, and compared. My bet would be on pure lens.

And ISO 3200 isn't really high for a Nikon D3S. I set it to Auto ISO with a limit at ISO 10,000, though I sometimes allow 12,800 too.

Well, my Sony A55 will go to 25,600 under some conditions, and pretty good quality to 1600 but above that, noise becomes an issue. And it certainly is in the picture of the lark above. It is why I feel that if you took even one TC out, you might be able to bump up the aperture or reduce the ISO to 1600 and then crop.

Of course the image was post processed, and appropriately sharpened! So are JPEG images straight from the camera (though the "appropriateness" might be open to question). Read what kdog said to you about post processing in the other ongoing thread about that. He's dead on right.

Personally, I like to depend more on the equipment I’m using than on what can be done on a computer. Even on the equipment, when it allows, I like using manual controls (even if it is just controlling the DOF). Whereas, I could just shoot in program mode, and go home and fix everything, including introducing a pretty nice blur. But I think this point is best addressed in the post-processing thread.

I'm not sure I see a valid point there... :-) My point was that with a really really good 70-200mm zoom (the Nikon is certainly the best 70-200mm zoom ever marketed) it is even possible to get usable images when stacking TC's. That's a bit astounding, and it most certainly demonstrates that it is absurd to claim the use of a TC always results in "immensely" impaired sharpness.

My point was that adding lenses (TCs) in front of lenses will affect IQ. You seem to agree.

Different equipment and different types of photography present different problems and solutions. I very commonly use TC's for macro work. I very commonly use either a 1.4x or 2x TC on a variety of high quality lenses, with the mentioned 70-200mm f/2.8G VRII and the 400mm f/2.8 being the most often.

I have tried close-up shots using TC but never macro (but then, I am still shopping for a good macro lens, stuck on comparing Minolta 50mm/2.8 and 100mm/2.8 at the moment). But I think if maximizing IQ were a top priority, I would go for pure lens over putting a TC.

You probably meant to say diffraction; but in any case that depends more on the sensor size than on the lens, with Nikon's 1.5x cropped DX sensors showing some diffraction at f/11 and significant diffraction at f/16, but the 1.0x cropped FX sensors are the same at f/16 and f/22. Note also that HP Sharpen can virtually reverse the effects of about 1 or 2 stops of diffraction, so even with a DX camera it should not be significant until perhaps f/22 for a competent photographer.

Yes, my bad, I meant diffraction. But on any given camera set up, it depends on the lens itself. Most will hold it well until about f/8.0, some will be just fine at f/11. But sooner or later, it will play a role, and it almost always does around f/11 or smaller.

[Floyd_Davidson]

Originally Posted by EinsteinsGhost

It is, if your argument is to be focused on image quality as opposed to cost. If you say “but a 500mm lens costs thousands more”, you are helping make the point opposite yours that using smaller focal length lens plus TCs is a cheaper alternative to getting similar results at a budget price as opposed to same results at a high cost. Note, similar would imply a compromise. There is a reason such focal lengths in a quality lens come at a price.

I don't see the "make the point opposite to yours" at all. Saying that cost has no significance when the differential is more than 2x the cost of what most people have even invested in both a camera and a lens combined is not valid.

I think you might be surprised. The only solution might be to take a good prime (say, 200mm) and take identical test shots at the optimal aperture with one and then two TCs, all cropped for identical frame, and compared. My bet would be on pure lens.

That, however, entirely misses the point!

Well, my Sony A55 will go to 25,600 under some conditions, and pretty good quality to 1600 but above that, noise becomes an issue. And it certainly is in the picture of the lark above. It is why I feel that if you took even one TC out, you might be able to bump up the aperture or reduce the ISO to 1600 and then crop.

That again simply misses the point. ISO 1600 might well have significance when using a Sony A55. It is barely noticeable with a Nikon D3S, but that still misses the point.

Clearly if one can get a usable image with stacked TC's on that lens it is not correct to claim that any use of a TC will cause immense loss of sharpness.

Personally, I like to depend more on the equipment I’m using than on what can be done on a computer.

Lots of people enjoy setting up artificial handicaps for any number of different endeavors, and that is quite acceptable. The problem comes when people don't realize that it is just an unnecessary handicap, and particularly when people foist it off as more appropriate than not.

Personally, I like to make good photographs. I use every "trick", with whatever tools I have, to produce the kind of photographs that to me represent "good". I agree with what Ansel Adams said, I don't take pictures, I make photographs.

Even on the equipment, when it allows, I like using manual controls (even if it is just controlling the DOF). Whereas, I could just shoot in program mode, and go home and fix everything, including introducing a pretty nice blur.

I think you are very mistaken about that! Post processing doesn't "fix" anything. The way to make a great photograph is get a great shot and process it correctly.

My point was that adding lenses (TCs) in front of lenses will affect IQ. You seem to agree.

But the question is when will it affect something more than is acceptable, as opposed to perhaps an effect that cannot even be detected?

I have tried close-up shots using TC but never macro (but then, I am still shopping for a good macro lens, stuck on comparing Minolta 50mm/2.8 and 100mm/2.8 at the moment). But I think if maximizing IQ were a top priority, I would go for pure lens over putting a TC.

Well, if you ever get more deeply involved in photomacrography, read the John Shaw book I mentioned previously.

A very good example is that a lot of people need to have a back-packable field kit, and find (as I do) that a very high quality 105mm f/2.8 manual focus macro lens plus a Vivitar 2x Macro Focusing TC (which I use most often, or the Panagor model that was used in the flower pictures posted previous), or some similar combination is just an ideal kit. I'm not sure about compatibility issues with older Minolta lenses, so I don't know if those are available or usable with the Sony A55, but it would certainly be worth investigating. The combination of a light weight 105mm and 210mm macro lens is very useful.

But on any given camera set up, it depends on the lens itself. Most will hold it well until about f/8.0, some will be just fine at f/11. But sooner or later, it will play a role, and it almost always does around f/11 or smaller.

The aperture and the sensor size are the determining factors. I could just as easily say that for any given lens it depends entirely on which camera it is mounted on.

There just isn't much variation from f/11 on this lens to f/11 on that lens. Regardless of that, as noted diffraction can be countered, up to about 1 or 2 stops, with a high pass filter in software. And beyond that you'll note that serious devotees of photomacrography continue to shoot at f/32 and sacrifice diffraction for greater depth of field, which provides a good measure to keep diffraction in perspective.

[EinsteinsGhost]

Originally Posted by Floyd_Davidson

I don't see the "make the point opposite to yours" at all. Saying that cost has no significance when the differential is more than 2x the cost of what most people have even invested in both a camera and a lens combined is not valid.

What has cost got to do with comparison of image quality? Is it the quality of image itself?

That, however, entirely misses the point!

There was no point. There was an assumption being debated. Yours: you won’t see any difference. Me: You would. The only way to find out would be to test it out (I have, but not using it for argument because then you might blame the quality of TC, hence you should do it yourself instead of assuming).

That again simply misses the point. ISO 1600 might well have significance when using a Sony A55. It is barely noticeable with a Nikon D3S, but that still misses the point.

But at ISO3200 the image quality is poor from the D3S (I assume that is the camera used), way too much noise. I am sure the quality would be better at ISO1600.

Clearly if one can get a usable image with stacked TC's on that lens it is not correct to claim that any use of a TC will cause immense loss of sharpness.

But the question is when will it affect something more than is acceptable, as opposed to perhaps an effect that cannot even be detected?

May not be “immense”, but that IQ is affected. That was the point, not the degree of loss. Your original argument (much less in a derogatory way towards David) was that there is no effect on sharpness with use of TCs.

Lots of people enjoy setting up artificial handicaps for any number of different endeavors, and that is quite acceptable. The problem comes when people don't realize that it is just an unnecessary handicap, and particularly when people foist it off as more appropriate than not.

That is fine! Not a problem at all.

I think you are very mistaken about that! Post processing doesn't "fix" anything. The way to make a great photograph is get a great shot and process it correctly.

What do you process a photograph from the camera for, if not to fix anything? But as I said, this argument is best left in the other thread.

Well, if you ever get more deeply involved in photomacrography, read the John Shaw book I mentioned previously.

I will. Thanks!

A very good example is that a lot of people need to have a back-packable field kit, and find (as I do) that a very high quality 105mm f/2.8 manual focus macro lens plus a Vivitar 2x Macro Focusing TC (which I use most often, or the Panagor model that was used in the flower pictures posted previous), or some similar combination is just an ideal kit. I'm not sure about compatibility issues with older Minolta lenses, so I don't know if those are available or usable with the Sony A55, but it would certainly be worth investigating. The combination of a light weight 105mm and 210mm macro lens is very useful.

But what specific advantage would using a TC on a macro lens (I am leaning towards Minolta 100mm/2.8 or Tamron 90mm/2.8) provide? We know the disadvantages, that it will make for a slower lens, and possibly worsen auto-focus speed as well (macro lenses aren’t the best bet for it to begin with).

The aperture and the sensor size are the determining factors. I could just as easily say that for any given lens it depends entirely on which camera it is mounted on.

Diffraction is a characteristic of the lens itself. If a lens diffracts significantly at f11, that characteristic won’t change on a different camera. It will simply do what it does on any camera body the lens will fit. How much pronounced it can be on a sensor (or film) would depend on the resolution of the image tself.

There just isn't much variation from f/11 on this lens to f/11 on that lens. Regardless of that, as noted diffraction can be countered, up to about 1 or 2 stops, with a high pass filter in software. And beyond that you'll note that serious devotees of photomacrography continue to shoot at f/32 and sacrifice diffraction for greater depth of field, which provides a good measure to keep diffraction in perspective.

Weather permitting, I should have ample opportunity to take landscape photography next month. For trial purpose, when controlling aperture, I have traditionally stuck with f16 or lower (hence accepting some diffraction, because we know it is pretty much unavoidable after f11. I don’t think I would try the smallest apertures on the lenses though. May not be much of an issue on large format cameras of the old days and such, but the effects will likely be more pronounced on APS-C sensor.

[blueflames50]

you got my interest in more on the TC with macro lens now....have a nice prime Nikon 60mm macro...had not thought of using a TC with it until now...interesting...more info please! an here I was going to save up for a 100 or so mm macro lens...hummmm...