equipment recommendation - What size lens is recommended for flying bird photography?

My wife has a Canon 450D and a 70-300 lens for long distance shots.

I am considering a present or two and good advice from jrista suggests possible upgrade of camera to a Canon 7D and of lens to a Canon EF100-400 or Canon EF400 (I do like Canon). This will result in quite a large investment in my wife’s photographic future and I would like to get it right.

I would, therefore, welcome any further advice from jrista and any other users who may be able to assist me in my quest.

If I were only able to get one of the presents, which should I choose?

Answer

I'm not a bird photographer but whenever I travel with amateur birders, they almost always use the Sigma 50-500mm. As Jrista said, you lose in terms of quality but versatility-wise it is hard to beat.

The question is where the images go, if it's for small prints or web-use, you may not notice the difference. If it's for a gallery, you'll have to get something better and probably heavier.

When I take a group to Ecuador, we spend two shoots (sunset & sunrise) at a bird-lodge sanctuary. The species are quite small, particularly the hummingbirds everyone goes to see there. Those who max-out before 400mm (like me) didn't get many closeups, except near the bird-feeders where you can get really really close. At least, I'm not there for the birds ;) Those who don't want to shoot birds, get to have fun photographing Orchids instead.

composition - Still-life reconstruction considered plagiarism?

I am really bad at still lifes. That is, I never even attempted making one. So I decided to try and make a photo of freshly baked bread. I stumbled across a few amazing shots on the Internet which I want to repeat. If I ever published my photo, would it be considered plagiarism? In the end, all I want to do is to copy with my own tools a photograph I have found online.

If I have tried to replicate another photograph, with the same utensils and composition, could mine be considered plagiarism?

Answer

There is a long, time-honoured tradition in the art world of learning by copying. In fact, in bygone days one would have trouble walking through an art museum because of all of the easels set up. (These days it isn't allowed, mostly because of tripping hazards, wet paint and liability issues, not because of the copying thing.) But publishing is another matter. Even when the original work has slipped into the public domain (or is under a CC0 license), it would be considered bad form to pass the copy off as an original. Tradition holds that faithful copies be published with a title something like "Study after [original artist]", even though in such cases you actually may hold all rights in your copy.

It gets more complicated with works under current copyright. If you have created a faithful copy, you may not hold usable rights in the image (or other work). That would depend on obtaining the right (license) to create a derivative of the work you are copying. It's really, really hard to claim accidental similarity if you've used the same subject, the same lighting, the same major composition and the same props and utensils in the same positions. It's no different, really, than creating a drawing of a photograph — it's still a derivative work, even if you've used a different medium to create the derivative. If you're proud enough of what you've done to consider publishing, then you'll probably need to get permission from the original photographer. And don't be surprised if any grant of license prohibits commercial use.

The object of the game, though, shouldn't be to copy for the sake of copying, but copying to understand. Why does that arrangement of elements look attractive? What is it about the lighting, the point of view, the field of view, etc., that makes the elements of the picture look that way? How can I apply that to my own work? When you've taken in the lessons learned and applied them to your own original work, then you've got something you can take real pride in. More than that, you've demonstrated to yourself (and can demonstrate to others, including potential clients) that you understand lighting, composition and camera settings well enough to create similar (not identical) images on demand. And that's what the lessons of copying are meant to provide.

exposure - Lighting up a subject during sunset without a flash?

I’ve recently been trying to experiment with sunset portraits but I keep encountering a problem where the sky is lit up exactly how I want it but the subject is under-exposed, with little to no exposure. Is this having to do with metering or will manually exposing the image help? This was shot at f/4 and I’ve heard suggestion on bumping up my exposure compensation meter.

metadata - How to add keywords to lightroom from a textfile (after import)?

I have a fairly large (20,000 photos) catalog. I'm trying to add keywords from the exif data that lightroom doesn't read, for instance any effects (like "pop color") applied to the photo.

Using exiftool I extracted all the data I want, and now I have a long text file like:

./2012-12-30/DSC03532.JPG   effect-Partial-Color-Blue

./2012-01-07/DSC00353.JPG   effect-Partial-Color-Yellow
...

And now I'm trying to figure out how to get that data into lightroom as keywords. I know I can write the keywords to the files directly and then have lightroom import them, but doing so wipes out all existing keywords I have on the files in lightroom.

Any insight?

digital - Can a focal reducer be used with a teleconverter?

Can you use a focal reducer with a teleconverter? I don't believe it would be possible to do it but, is it?

If I were to use a full-frame 50mm lens on a 2x teleconverter with a 0.71x focal reducer on APS-C, would it work? Would I also get the benefit of an extra stop of light from the focal reducer?

Answer

Theoretically, optically, it would work (for low-quality values of "work").

Yes, the focal reducer would give an extra stop of light. But because the 2x teleconverter is responsible for 2 stops of light loss, you'd still net 1 stop of light loss.

Aside from the optics math, there are some real practical problems with this approach. Depending on exactly which 50mm lens(es) you're talking about, some of them have rear elements that sit quite far back. And depending on which teleconverter(s) you're talking about (especially 2x teles), the teleconverter might intrude into the lens's space. So it is very possible that a 2x tele will not mate a certain 50mm lens.

Generally, wide-angle and normal focal length lenses are not meant to be mated with teleconverters. It's tempting to think of lenses, filters, and teleconverters as sort of snap-together, Lego-like modular components that can be stacked together and added onto. Physical mating-wise, that is true. But everything you add in the optical path has drawbacks. And items that weren't specifically designed to work together will have worse combined drawbacks than items that were meant to work together.

Teleconverters have real, visible downsides (loss of light, some degree of loss of quality or sharpness, etc.). Those downsides are acceptable to turn a 200mm lens into a 280mm or 400mm lens, without having to carry such a monstrous beast (with the corresponding monstrous price). But those downsides will quickly turn a nifty 50 into a crappy 70 or 100, when those are already readily available without compromise.

Real-world teleconverter compatibility

Nikon's AF-S Teleconverter Compatibility page shows that the widest lens any of their teleconverters support is the AF-S VR Micro 105mm ƒ/2.8G IF-ED, and even then, autofocus is not possible with that lens combined with any of their telecons. The rest of the primes that are supported are all 200mm or longer. The widest supported zoom lens is the 70-200mm ƒ/2.8.

The widest lens on Wikipedia's List of compatible EF lenses for Canon's teleconverters is the 135mm ƒ/2L USM; after the 180mm ƒ/3.5L Macro USM, the rest are 200mm and longer. (Except for the tilt-shift lenses, but they are special cases).

Sigma's Teleconverter Compatibility page is slightly more confusing (because of the new teleconverters to support the newer Sports and Contemporary lenses, vs. the older telecons for their older lenses, and because of the different mounts they support). However, none of their teleconverters support Sigma prime lenses wider than 105mm.

Current Nikon and Sigma teleconverters are more-or-less brand specific — don't bother trying to mix a Nikon teleconverter with a Sigma lens, or vice-versa. See this Sigma 2.0x Teleconverter Review at photographylife.com:

One of my biggest frustrations with the Sigma 120-300mm f/2.8 Sport lens, was the fact that it will not take any of the Nikon teleconverters – they simply will not physically mount. I am not sure if there is a technical reason for not allowing that, but given that teleconverters are mostly “pass-through” lenses for magnification purposes, I initially did not think that I would be faced with any cross-brand compatibility issues. It turns out that teleconverters are very brand-specific. Nikon teleconverters are designed to only work well with Nikkor lenses, while Sigma teleconverters are designed to only work well with Sigma lenses. So if you were thinking of buying a Sigma 1.4x teleconverter to be used for a Nikon telephoto or super telephoto lens – forget about it. Even though the Sigma 1.4x will physically mount on any Nikon telephoto lens that can take teleconverters and it will perform well optically, it will cause all kinds of lens communication and autofocus issues.

Canon teleconverters are not so limited in their compatibility with third party EF lenses. See this answer to Compatibility of Canon extenders with non-Canon lenses. Also related, Can the Sigma TC-1401 1.4x Teleconverter be used with Canon lenses?

flash - What is "Dragging the Shutter"?

I've heard this term of "dragging the shutter". What does this mean and why would I use it?

Answer

It just means using a long exposure, usually in the context of mixing flash with ambient light, in order to let in more ambient light to better expose the background. See this related question:

How does dragging the shutter work?

What is the difference between using an ND filter versus 2 polarizers?

I know what an ND filter does. I know what a polarizer does. I also know what two polarizers stacked together and rotated properly do.

So the question: why should I use an ND filter to achieve a darker image at the input, when I can use 2 polarizers instead and rotate them to exactly as dark an image at the input as I want?

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Also asked by Julien Gagnet

Is it possible to use two polarised filters to create a variable ND filter?

I was reading that by attaching two polarised filter we could create a variable ND filter.

Has anyone done this? How was this done? Any drawback (colour cast, quality...)? What would be the strength in light filtering of such filter?

Answer

• 
  

  Polarizers are often more expensive than ND filters and you need two of them.

  
  



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  Stacking two filters can cause vignetting with wide lenses.

  
  


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  You have an extra glass surface with two polarizers which can cause flare and potentially loss of contrast/sharpness.

  
  


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  This arrangement can cause colour shift toward yellow (but so some ND filters).

  
  


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  Extreme wide angle lenses will exhibit uneven darkening due to the difference in incidence angle across the polarizers.