What is the maximum distance for getting good SHARP pictures on a telephoto lens?

[astroNikon]

I didn't see anyone mention on how you are holding the camera. I know because I was really reallly bad hand holding it, now I'm getting much better.
See this thread
http://www.thephotoforum.com/forum/...-making-yourself-tripod-versus-using-one.html


and how sharp, as one mentioned, the Moon. I started shooting in Raw mode and the sharpness of my moon pictures shot up dramatically. I've always been careful on the tripod so I'm putting the improvement to the Raw file usage. The detail when I zoom in to the original is quite incredible.
http://www.thephotoforum.com/forum/general-gallery/337050-moon-8-19-2013-a.html

I bought Lightroom last year, but only now started using it when I jumped to Raw files. It is confusing (and I'm an IT person for 25 yrs) but just have to learn the basics then it all starts making sens with the "workflow" from one step in the process to another (Import/Load into a Collection, then Process the image)

 

[Solarflare]

[...] I tried a 18-200mm lens (kit lens,so higher apurter #'s), a Tamron 70-200 2.8 ,and now a nikon 70-300(higher aperture #'s (4-5.6 I believe) is doing the same thing. It still didn't matter with the 2.8 lens either. [...]

First of all, telezoom lenses are always the sharpest of all lenses. Thats because light has to be bent less than with a normal or a wide lens. DxO mark for example rates the Nikon AF-S 200mm f2 VR lens as the sharpest lens they have tested so far. I wonder if the Nikon AF 200mm f4 micro will be even sharper; DxOMark has not yet tested that one last time I checked, and macro lenses are usually sharper than other lenses. Another extremely sharp optics is the Nikon AF-S 85mm f1.8.

I definitely can get sharp images on my own AF-S 70-200mm f4 VR easily. Its definitely possible and distance is no issue whatsoever in such a task.

The AF-S 18-200mm f3.5-5.6 VR is NOT a kit lens and NOT a telezoom. Its a superzoom. You cannot expect maximum image quality from a superzoom, even if the Nikon superzoom has a very good name, for a superzoom.

The Tamron 70-200 f2.8 is, well, a Tamron. I have no clue about its quality.

The AF-S 70-300 f4.5-5.6 VR however is definitely a very high quality zoom. You can definitely get razor sharp images with that one.


The reasons why an image isnt sharp can be, for example:
- Bad focus. What you wanted to photograph isnt sharp. Often something else, in front, or behind, is, thats how you can detect that. It should be noted that lenses may be poorly calibrated, which results in focus errors even if you focussed correctly.
- Too slow shutter speed without compensation. You are taking pictures at low shutterspeeds without a tripod (plus technologies like mirror lock up, remote release etc for critical subjects, such as macro work) or without sufficient image stabilization. That can be optical, sensor or digital stabilization, or simply stabilization from good posture, breathing out before taking the picture, using natural support such as leaning against a wall, etc.
- Too slow shutter speed for a moving subject. This depends upon the speed of the subject and in what direction it is moving, relative to the camera - sideways is a lot more critical than if its moving right at you. To make a sharp picture of a flying bullet, for example, you need a shutter speed of 1 µs. This is done with special cameras and special flashs, though. With an ordinary camera, you can only reach about 1/8000s of a second, and using a flash for freezing the subject only gives you about 1/40,000 sec (with a Nikon SB910). For sports, 1/500 to 1/1500sec is usually sufficient.
- High film speed. Digital sensors can amplify the analog signal from the photodiode before performing the A/D conversion. This is expressed as ISO. Typically the non-amplified ISO of a sensor is between 80 and 200. Every doubling means the signal is boosted by the factor of 2 again; every time this happends, the noise from the photodiode is also amplified. In the end, the signal gets more and more poor. How well a sensor can take high ISOs depends upon the sensor. A D7100 should be able to handle ISO up to 1600 quite well, depending upon your standards.
- Maximum aperture. Many lenses need to be stopped down one or two stops for best results. How much this does depends upon your lens.
- Poor quality optics. Some lenses simply get sharper than others. Thats a question of tolerances during production, and of course the individual lens might be sharper or softer than other lenses of the same type.
- Reflections inside the glas. Again poor quality optics will reflect the light a lot between its surfaces, resulting in bad picture quality.
- Diffraction from very close apertures. At f/8, the current high resolution cameras start to see diffraction. At f/16 and above, its very apparent. Lower resolution cameras like the Nikon D4 are a bit more tolerant to this effect.
- Foggy/dirty lens. Yes, that can happen, too.
- You are looking at the 100% resolution on a computer monitor. Nikon uses Bayer color filters. Thus, the 100% resolution CANNOT POSSIBLY be completely sharp. For that you'll have to use Foveon X3 sensors, but these only really work well at ISO100, while I can choose ISO6400 for still quite good results on my new D600. The Leica M Monochrom(*) is another example for a camera that can be perfectly sharp (but also doesnt have colors).

I think 1/250 and 1/125 was just too slow for the 300mm.

Well, that depends on if you use VR, or not. With VR, I can pretty reliably take pictures at 70mm on my 70-200mm at 1/13 sec.

Raw images MUST BE sharpened; that's not a preference but a fact of the process.

I shoot raw, but most of the time, I leave the sharpening slider at 0, because it doesnt really improve the picture, not on the large scale anyway, and in the small scale the picture gets unnaturally harsh.

I DO use the sharpest glas I could find, though.



(*) Yes its "Monochrom" not "monochrome". Leica is a german company and the german word for monochrome is "monochrom". And the "M" of Leica M stands for "Meßsucher", which is the german word for "rangefinder".