[stevebrot]

The TC can't invent details not "seen" by the main lens, but by magnifying it could make apparent details the main lens transmits that might not be evident using the main lens alone.

Yep...the discriminator is the pixel density at the sensor for the comparisons. The TC shot always has higher potential for data capture per degree of arc than the non-TC shot. Shooting at different distance to normalize FOV at the sensor should show whether the TC degrades the image.


Steve

[mgvh]

I'll simply add some non-technical but practical observations I have made while shooting with telephotos with or without teleconverters. I'll use the examples I just shot using a Super Takumar 300mm F4 and a Kenko Pz-AF 1.5X Teleplus SHQ and a Focal MC 2x Teleconverter. (The Kenko is the higher quality 1.4x one. The Focal is your typical cheap 2x.)

1. Shooting at these lengths, the biggest issue for me is getting the focus right. I can get more right with no TC because I have a bit more depth of field. I can sometimes get a better shot with the TC since I can see it (whether through the viewfinder of LiveView) better.
2. There is more to the picture than simply detail. All the other things we use to evaluate a pic also come into play. E.g., the Focal 2x adds some glow to a pic.
3. I can usually get the best picture when I'm shooting at the focal length I really want. E.g., if the object I want is best in the frame at 300mm, it doesn't do me any good to back up and use a TC to get the same field of view. If the object I want is really best fit to frame at 450mm, then I'll do better using the Kenko 1.5x than no TC and 'enlarging.'
4. The chimney shot below also shows how this works. When I have to 'enlarge' to 200%, I'm going to start to get some pixelization that can't be overcome by the sharper image.
5. Shooting to the right size also has the advantage of metering more accurately. In the chimney shot below, the SuperTak without a TC had lots of bright sky in the pic, so the chimney was dark and had to be brightened. With the Focal 2x, the chimney filled more of the frame and hence the metering was more accurate.
6. The other issue is that even with a rather fast lens like the SuperTak 300 f4, I like to stop it down to f8 to get the best pics. Using the TCs is really starting to affect the light which means slower shutter speeds which means more likelihood of shake.

So, here are two of the best examples to show what I mean. Shooting with a K-30, tripod, 12sec delay, focusing using LiveView enlarged, all shot using AV, all set to the right shake reduction.
With the ruler shots, the order is Kenko 1.4x (at 145%), Focal 2x (at 100%), SuperTak alone (at 200%). All shot at f6.3 from about 50 feet away. No processing. What appears on my screen is that the Kenko is the best and attests to its somewhat better quality. You can also see the glow with the Focal (point 2 above).
With the chimney shot, both were shot at f8, first is ST at 200% and then w/ the Focal at 100%. I'm guessing the chimney is about 70 yards away. These pics were corrected a bit to try to get a better pic with quick editing in Faststone. I tossed the Kenko shot, because I didn't get the focus right. (Cf. my first point above!) On my screen, the SuperTak does have better detail, but if that's really the size shot I want, I'd probably take the Focal because it doesn't have the pixelization showing up at 200% view. (Points 3 and 4)
So... depending on my lenses, even a cheap 2x TC might provide a benefit. In practice, I tend to use my DAL 55-300 the most because it does a better job of focusing than I can. I do use the Kenko w/ the DAL, since it does have all the contacts and the focusing actually works rather well.

[GeneV]

On a practical note, the application where I see the most added detail from a TC with a quality lens like the DA*300 is with photos of smaller birds. The detail in the feathers draws sighs.

[Simen1]

Just take out the lens, then you can use it as an extension tube for macro.

Thanks, thats a great idea!

[bdery]

The TCs allow us to capture detail not available in the DA*200 image by itself.

When your lens greatly outresolves your sensor a good TC could give you mere detail.

D1N0 nailed it.

If the TC adds detail, it means the lens is not limiting your image, the sensor is.

The TC cannot create information that isn't there, so if the TC adds apparent detail, it means it was there in the first place.

[goatsNdonkey]

bdery,

Yes, trying to keep clear where the added detail becomes apparent is important. If we are measuring the detail in the finished image, then adding the TC can increase the detail there. But concluding that the TC itself was the origin of that detail seems mistaken. But can it be such a worthy collaborator that it deserves serious credit? mgvh's post supports giving TC's, in his experience, that level of credit. And then, too, there is the question of whether certain TC+lens combos offer superior results compared to the average TC user's experience. And also the question of whether the results are analyzed on film or on the output from a particular sensor...which may actually cloud the issue more than clarify it.

[normhead]

But concluding that the TC itself was the origin of that detail seems mistaken.

Detail is outside of the lens systems. TC , prime or zoom doesn't matter. All they do is transit it.

And then, too, there is the question of whether certain TC+lens combos offer superior results compared to the average TC user's experience. And also the question of whether the results are analyzed on film or on the output from a particular sensor...which may actually cloud the issue more than clarify it.

Not if the answer is, "you have to test the TC you want to use with the lens and sensor combinations you want to use them with". That's not cloudy at all.

Every sensor is going to be different.
If you shot a 25-400mm equivalent image on an FZ1000 you can get 2700lw/ph on a one inch 20MP sensor.
If you shoot the Sigma 70 you can get 2800 on an APS-c sensor.

In my image above, where the K-3 and DA*200 can't resolve the lettering on the first test shot, if I put that same DA*200 on a Q and used the same central focus point at the same distance, I can practically guarantee you the same lens will resolve that lettering perfectly. If I had a Q I'd do it and post it.


ON digital, every time you change sensors you're going to have to test, results on the K-5 are not going to be the same as on a K-3 or a K20D or a K10D, or a K100D.
On film, where you have larger grains as film speed increases, you're going to have to test every film you use.
It's going to require a lot of work to make this a science. Trial and error with your preferred equipment is the best approach at least for people with my intelligence. Maybe the smart guys can come up with something better.

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Last edited by normhead; 05-25-2016 at 08:20 AM.

[goatsNdonkey]

Detail is outside of the lens systems. TC , prime or zoom doesn't matter. All they do is transit it.



Not if the answer is, "you have to test the TC you want to use with the lenses you want to use them with". That's not cloudy at all.

On the second point, I agree. But that works energetically against the idea that we can make blanket generalizations we might be tempted to make, against or for the typical TC. It's really about what you've got in your lens and accessory kit and how it works in your shooting on the camera body you are using.

Of course, hearing about the success or failure of certain combos (lens/TC/camera) in shooting certain kinds of pictures could be useful for others able to try the same or similar combo for similar photography.

[normhead]

On the second point, I agree. But that works energetically against the idea that we can make blanket generalizations we might be tempted to make, against or for the typical TC. It's really about what you've got in your lens and accessory kit and how it works in your shooting on the camera body you are using.

Of course, hearing about the success or failure of certain combos (lens/TC/camera) in shooting certain kinds of pictures could be useful for others able to try the same or similar combo for similar photography.

And that's what we need. A list of situations people find the TC useful. IN my situation, small birds that are being magnified to many times life size, and which rarely fill the frame, a TC is wonderful for getting closer and increasing feather detail. But, I always have to balance that with giving up the f-stop, which a in lower light can affect speed of auto-focus, and a slower shutter speed.

At the end of the day, I take the TC off because I need all the light I can get, and move to a closer location. I only get pictures of the birds that aren't skittish. But, I get some good images. With the TC on, I'd get nothing. There is a point when every image you take has motion blur because your shutter speed is so slow, taking off the TC can get you another 15-30 minutes shooting. And this is the biggest reason I've ended up with the DA*200 ƒ2.8 and the TC. AT the end of the day a Bigma never gets me more than ƒ4.5. I'd lose at least a half hour of shooting. With stacked TCs the 200 gets me out to 500mm in a much lighter package that opens to ƒ2.8 in it's widest configuration. That's something TC's offer, that a zoom system can't. There simply are no zoom systems that can go to 476mm and can shoot quality images at 800 ISO, that offer an ƒ2.8 aperture @200mm equivalence, in their widest configuration. Not on any platform.

[kp0c]

And that's what we need. A list of situations people find the TC useful. IN my situation, small birds that are being magnified to many times life size, and which rarely fill the frame, a TC is wonderful for getting closer and increasing feather detail. But, I always have to balance that with giving up the f-stop, which a in lower light can affect speed of auto-focus, and a slower shutter speed.

At the end of the day, I take the TC off because I need all the light I can get, and move to a closer location. I only get pictures of the birds that aren't skittish. But, I get some good images. With the TC on, I'd get nothing. There is a point when every image you take has motion blur because your shutter speed is so slow, taking off the TC can get you another 15-30 minutes shooting. And this is the biggest reason I've ended up with the DA*200 ƒ2.8 and the TC. AT the end of the day a Bigma never gets me more than ƒ4.5. I'd lose at least a half hour of shooting. With stacked TCs the 200 gets me out to 500mm in a much lighter package that opens to ƒ2.8 in it's widest configuration. That's something TC's offer, that a zoom system can't. There simply are no zoom systems that can go to 476mm and can shoot quality images at 800 ISO, that offer an ƒ2.8 aperture @200mm equivalence, in their widest configuration. Not on any platform.

In your real life shooting scenario, is the need to unmount the lens and then mount the TC sometime a problem in the sense that you are missing shots that you could possibly have gotten with a "slower" but possibly more versatile* zoom lens?

I understand everything is a compromise, but still curious how you manage this situation.

*versatile as in fov coverage, not light gathering ability.

[normhead]

In your real life shooting scenario, is the need to unmount the lens and then mount the TC sometime a problem in the sense that you are missing shots that you could possibly have gotten with a "slower" but possibly more versatile* zoom lens?

I understand everything is a compromise, but still curious how you manage this situation.

*versatile as in fov coverage, not light gathering ability.

Anytime you switch from a zoom to a prime you run the risk of missing images. Sometimes I sit out int he blind with the 60-250 and 1.4 with the 200 and 1.7 on the little table in front of me. Especially with bigger birds, in my case jays , Grackles grosbeaks etc. the zoom will allow more framing options etc. For small birds where cropping is expected anyway, the fixed FL with maximum performance is the way to go. Once you're going to crop at least 30% of your image, and you can't frame with the zoom anymore, the zoom loses a lot of attractiveness. That turns the 60-250 into a fixed FL 250mm lens (350 is the 1.4) that is a lot heavier than it needs to be. But I miss good long shots because I have the zoom on, and I miss shots where the birds have come in really close to me, that I would have a much better image if I'd had the zoom on and could crank it back. SO what are you going to do? There's no set up where you get the best image every time.

What I do is go out, decide in advance, what I am shooting for that day, and set up appropriately. I'm going out knowing that there will be certain images I won't be set up for, but I will focus on getting the image that the lens/tc combo on the camera can handle. If I'm set up for a small bird at 20 feet and I get a big bird at 8 feet, I've missed out. But in my experience, it's better to go out with a purpose and stick to it, than it is to be messing around changing focal lengths. TC or zooms, it doesn't matter.

Example, I set up for a bird in a certain area, a bird comes closer. I think it will. I really want to get that image. I take off the TC or crank the zoom ring. The close bird hear's the noise or sees the motion and leaves before I get an image. A bird comes to the area I was set up for. Before I can get the zoom cranked back out or put the TC back on that bird leaves. I then lose the shot I spent a half hour setting up. If this happens to you enough times you start to realize, you need to shoot what you're set up for. That's where you time commitment is. If you really think you need to jump around bring a second body for the second lens. But understand in wildlife there are many situations where the only way your going to get the image is if you are perfectly still. Cranking a zoom or changing a TC is going to spook your target. So limiting yourself to what you are set up for is critical with wildlife present.

There is nothing that is going to help you with these kinds of things but you but getting out and shooting. I can tell you about what i do, but in the end, you aren't me, and you have to find out what works for you.

Here's an example.. I notice that this one bird keeps returning to this one branch right in front of me. I want the longest reach with the best AF, because I won't have time to focus the 1.7 with the bird so close, not to mention that this close 6 feet way" the noise of the 1.7 AF scares the birds. So I select the 60-250 with the 1.4 TC. That gives me 350mm with very good AF. I set up with the camera pointed to the spot and my face already in close proximity to the viewfinder. I hope the bird will land. When the bird arrives, all I have to do is press the shutter release. I'm lucky, the bird arrives lands in the same place he did a few minutes ago, I fire off a burst, mabey 6 frames before he takes off. Two of the images are good. I get exactly the image I hoped for. Not because I was busy trying to adjust to what was there, but because I anticipated what was going to happen, and set up for the shot I wanted before it happened. I'm just afraid discussing the relative merits of trying to capture shots on the fly might take away from the discussion of the importance of preparation.





I don't have any images like this taken "on the fly." meaning changing my TC or cranking a zoom. The best images require you to be ready and waiting IMHO. And I probably missed a couple other decent images while waiting for this image to happen. But, I wanted this image, so I don't care. A lot of the time your real choice is "do I want a chance at a great photo, or am I going to settle for an average type photo. After you've taken enough average type photos, the thought of another one really doesn't do much for you.

[kp0c]

What I do is go out, decide in advance, what I am shooting for that day, and set up appropriately. I'm going out knowing that there will be certain images I won't be set up for, but I will focus on getting the image that the combo on the lens can handle. If I'm set up for a small bird at 20 feet and I get a big bird at 8 feet, I've missed out. But in my experience, it's better to go out with a purpose and stick to it, than it is to be messing around changing focal lengths. TC or zooms, it doesn't matter.

Nice detailed answer, thank you! The part I quoted very well summarize what I began to notice lately during an assignment and confirms my feeling that I should most of the time stick with what I had planned instead of trying to chase every possible good image I see around.

[UncleVanya]

Analysis Paralysis or focal length chaos - either way you make a decision and stick to it if possible. Sometimes you have an opportunity you must chase but that's rare and not necessarily birds. You chase - you may fail but you try. This only works when you will not miss something by being out of position.

[luftfluss]

Timely that you posted this, Norm, as I've just begun exploring the A400/5.6 + K T6-2X over the last couple days.

No matter the challenges, difficulties, and loss of optical clarity, there is a sense of satisfaction when one can produce a frame-filling image of one's diminutive quarry.

[normhead]

Every now and then I nail one with the A-400 and the 1.4. but, it's been a while. With the 1.4 it's still plenty sharp enough. With the 1.7 I think you are testing the resolving power of the lens.