Josiah, from your brief description it sounds to me like you're probably grappling with two different things, each of which is a bit complex in its own right as to what is going on and what to do to improve it.
most of my photos (even without the extender) seem to be grainy.
The extender won't have anything really to do with images that are grainy. Not directly, anyway. When you say "grainy" I presume you mean
noise, and that's a property of the camera sensor, your exposure settings, and your processing. It's not a property of the lens / extender optics.
The
7D is a camera that suffers from a good deal of
noise. Search the internet for "Canon
7D noise", or even just older discussions on this forum, and you'll find thousands of discussions on this topic. You probably need to improve several things to get the best results from this camera, in terms of clean images with minimal
noise. A few tips:
- Shoot in the best light you can.
- Use the lowest ISO you can. This includes not using intermediate ISO settings like 160. Stick with even ISO's like 100, 200, 400. There are long drawn out technical reasons for this with the non-pro Canon bodies, but the net result is that intermediate ISO values produce a worse combination of noise & dynamic range, and they're best avoided.
- Nail your exposure right on. In your Robin example, it looks to me like the original shot is under-exposed by perhaps as much as 1 full stop. The 7D will punish under-exposed shots with a lot of noise.
- Develop a good workflow with noise reduction tools.
- Also, improve your sharpening workflow -- in particular don't sharpen things that shouldn't be sharpened, like clear blue sky or blurred elements outside the depth of field, because mainly you'll be sharpening the noise and not any real detail.
I cannot seem to get any of my photos as sharp as ones I have seen on this website.
Photos that aren't sharp is a completely different topic from
noise & grain. Unsharp images can result from a host of factors, and there's an equivalently large number of things that can be done to improve.
- As noted, the 2X teleconverter on any lens will reduce the sharpness of all images. Some models of teleconverter are better than others, some lenses are better than others, but the 2X on any lens will be worse than that same lens by itself, or with the 1.4X teleconverter. Get closer to your subject and/or use the lens bare or with the 1.4X and results will be sharper, pixel for pixel.
- Shooting any lens with a wide open aperture generally will not produce the sharpest results possible on that lens. Typically stopping down 1 - 2 stops on the lens will improve sharpness a good deal; most lenses hit their sweet spot for balancing highest resolution vs. lowest diffraction softness somewhere in the f/8 - f/11 range. This varies from lens to lens, but it's an optical fact of life in most cases. Do some tests on static subjects with your lens at various apertures (with & without teleconverter) to learn where your gear's sweet spots are.
- If you're using autofocus on the 7D, it's possible -- I'd say actually probable -- that AF inaccuracy is hurting you unless you've specifically calibrated your camera + lens. Again there are thousands of discussions out there regarding AF accuracy of modern DSLR cameras in general, most recent generation Canon bodies in particular, and the 7D in specific. To test whether your AF accuracy is acceptable or not, set up your equipment with a static subject and focus on it using AF. Then kick the camera into Live View mode, zoom up to 10X magnification, and look at areas on the test subject that you expect should be razor sharp. Manually adjust the lens focus knob and see if you can improve focus. If you can, then either your camera needs to be micro-adjusted for the lens (which you can do, see threads here), or calibrated by Canon at a service center, or the AF accuracy simply isn't great. If the latter, that's a whole other story on its own; there are many debates on the reliability of AF on the 7D.
- Obviously there are exposure factors related to shutter speed that affect image sharpness. If shutter speed is too slow, then either camera motion and/or subject motion can blur the image. That doesn't appear to be a likely factor in your Robin test image since 1/1000s should have been enough for a sharp result. Having said that, once the combination of shutter speed and focal length reaches a crucial area, then long-lens technique becomes a factor. Good tripod support, stable shooting stance to minimize camera motion & damp any vibrations, etc. can be important in getting the sharpest results possible when you're up in the territory of 400mm and beyond. The longer the focal length, the more that tiny vibrations or camera motion can spoil critical sharpness of the result, especially when pixel-peeping the image at 100% with a camera like the 7D that has a high pixel density on its sensor.
- With longer focal lengths as well, you have to consider dust, heat haze, water vapor, and any other atmospheric conditions that may be between you & the subject. Often people do everything else right and still can't figure out why tack sharp images don't come out. It can be because of shooting a subject at a greater distance, through a proportionally greater mass of crud or distortion in the air. So again get closer if possible.
- All of that above can be done right and still need another nudge of help through effective sharpening workflow. That's also a big topic in its own right, there are many past threads on it plus some articles in the NSN articles archive.
Just a few thoughts, I'm sure others will chime in as well...
I would like to know if it is my setup or settings/skill that needs the most improvement.
As a general rule, always improve skills & technique first, equipment second. Better skill will help you no matter what gear you've got now, or get in the future.
Working on skills will also provide valuable info on what equipment in your setup may need to be improved, and what you can continue to live with and still get the results you want.
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