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Old Oct 11, 2011, 12:21 AM   #1
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Default Wide Angle Lens?

Please forgive my lack of knowledge. I'm a complete newbie when it comes to DSLR's. I had just started to learn video camera terminology when my HD camera was dropped into a pool. So I went out and got a Canon Rebel T3i. For what I do I need a wide field of view lens. I tride searching but it's all greek to me. Any suggestions would be much appreciated. The price limit is about $500.
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Old Oct 11, 2011, 1:59 AM   #2
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Hello!
http://en.wikipedia.org/wiki/Wide-angle_lens

well basically wide angle means more subjects in the picture. t3i comes with 18mm which is pretty wide! Most digital cameras comes with built in 28mm lens.

This might be the best and funniest explanation i could find
http://www.youtube.com/watch?NR=1&v=RE27-nT_wjs. You wont get any distortion with 18mm he's been talking about fisheye lens
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Old Oct 11, 2011, 5:59 AM   #3
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On a T3i, the Canon 18-55mm kit lens has a maximum angle of view of 74 20' (diagonally). What you're looking for is a lens that has a shorter focal length. Focal length is a measure of how much a lens bends light; the shorter the focal length of a lens, the more it bends light, and thus the wider its angle of view.

There are a number of good wide-angle and ultra-wide-angle lenses available, so you have lots of options. How much wider do you need than you can get with the 18-55. That is, what do you want to shoot? ... and how did you get it with your last camera?
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Old Oct 11, 2011, 4:25 PM   #4
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Thanks guys. Thats a good wiki article. So it's focal length. Gotcha. Well I like to shoot movies at work. The problem I run into is that I'm a pilot and the cockpit is pretty cramped. The 18mm is not too bad but I was hoping to get an even wider field of view to get nice shots of at least most of the cockpit from my seat. So i'm looking at something that is about 36 inches wide and 18 inches in front of me.
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Old Oct 11, 2011, 8:12 PM   #5
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Quote:
Originally Posted by Micro View Post
... So i'm looking at something that is about 36 inches wide and 18 inches in front of me.
That's a 90 horizontal angle of view (100 diagonally.) On a Canon APS-C body, you'll need something 11mm or shorter to get that.

The Canon 10-22mm has very little distorion and is sharp, but it has a lot of vignetting at the wide end.

The Sigma 10-20mm f/3.5 has a little more distortion, less vignetting wide open, but the corners aren've very sharp at the wide end.

The Sigma 10-20mm f/4.0-5.6 has more distortion and more vignetting, but it's a little sharper in the corners and it's less expensive than the other Sigma.

The Sigma 8-16mm is very sharp, but it has a lot of distortion and vignetting is a problem.

Tamron's 11-18 doesn't have much distortion, has little vignetting and is reasonably sharp except in the corners at the wide end.

The Tamron 10-24 has soem distortion, a lot of vignetting, but it's sharp stopped down.
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Old Oct 11, 2011, 8:58 PM   #6
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Good info on the lenses, TCav. I've been wondering about a wider lens (than my Sigma 17-70), but I have never liked the appearance of photos taken with fish-eye lenses. Is that the distortion you're referring to? In other words, what is the widest angle I could reasonably hope for to get flat images instead of fish-eye effect images? I'm shooting with a T1i crop body.
Thanks,
Dan
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Old Oct 11, 2011, 9:21 PM   #7
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TCav, awesome info on the lenses! Thanks bud. Gonna look into those. Thanks a ton!
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Old Oct 11, 2011, 11:05 PM   #8
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Hi Micro

TCav has given you a good summary of the lenses, and indeed useful info (as usual... well done TCav).

I can say that I have the Sigma 10-20mm f/4-5.6 and am very happy with the lens. It's very sharp (including corner to corner at the wide end which I use most). Build quality is very good.

When I bought it (over 3 years ago) several of the ultra-wide angle zooms that are available today were not yet on the market (eg Sigma 10-20mm f3.5, Sigma 8-16mm, Tokina 11-16mm).

The Canon 10-22mm was the main other option I was considering. But as I was on a tighter budget back and the Sigma 10-20 f/4-5.6 was about $400 dollars cheaper, I went with the Sigma.

The first copy of that lens I had included some noticeable decentreing (slight blur on one side of the photo, noticeable at the wider end). So I exchanged for another new copy (my current one). This one has only very slight decentreing, but I can overcome it and get corner to corner sharpness using manual focus.

As most of my ultra-wide photography using this lens is landscapes at 10mm, I usually stop down between f6.3 and f11 - and it's easy to get everything in focus with the very wide depth of field.

--------------

requa - to answer your question about distortions- what I'm quite sure TCav is referring to - is the 'barrel / pin-cushion' effect that lenses produce, which can sometimes be quite 'complex / wavy' - especially at the (ultra)wide end on ultra-wide zooms.

This can mainly be noticeable with 'straight lines' (eg particularly architecture) - and less so an issue for landscape photography. See the distortion charts on lens reviews at www.photozone.de to give you a visual diagram of lens distortion (which contain reviews for most, if not all, of the above lenses too).

The good thing is that several software packages can correct distortion in such lenses, some 'automatically' detect your lens and camera combination (eg DxO Optics Pro). So even architecture can look quite good (ie 'straightened up') with a bit of clever post-processing with any of the above lenses

I also greatly dislike the 'fish-eye' effect (this is not strictly speaking the same 'distortion' that I am describing above). The new Canon 8-14mm f/4 L is an interesting lens that it can produce fish-eye or 'flat' images depending on different focal length / camera body combinations.

So requa, the widest 'flat' lens you can currently get for a Canon APS-C (1.6x 'crop') camera body is the Sigma 8-16mm (many reviewers rate it positively). If you use a full frame camera body, you can use the Sigma 12-24mm (and there's a version II out now) which gives you about the same as the Sigma 8-16mm on a APS-C body, or maybe just a smigeon wider.

--------------

Micro, let us know how you go. A quick bit of advice is, ultra-wide angle lenses can be very challenging to take good photos with. Practice with it a lot. It can be quite important to remember to take photos very level in some situations, otherwise everything can look 'pushed back' or 'leaning forward' and give an artificial look.

The perspective at eg 10mm on a Crop body (16mm equivalent in full frame / 35mm format) is very wide, and can be used very creatively.

Looking forward to seeing some of your photos.

Paul
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Old Oct 12, 2011, 1:52 AM   #9
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PJ, wow, thank you! Slightly overwhelming but that is what I'm here to learn. Here is an idea of what I'm trying to get footage of / get shots of: http://www.youtube.com/watch?v=D6mhJo55P40

The tough part for me is that I try to get the exterior of the shot at the same time I try to get the interior / cockpit (which have very different brightness levels). If anyone has any suggestions on getting those shots it would be much appreciated! Thanks.
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Old Oct 12, 2011, 7:06 AM   #10
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Quote:
Originally Posted by requa View Post
... I have never liked the appearance of photos taken with fish-eye lenses. Is that the distortion you're referring to? In other words, what is the widest angle I could reasonably hope for to get flat images instead of fish-eye effect images?
The fisheye effect is actually a normal consequence of such a wide angle of view. The lenses I mentioned are all intended to project a rectilinear view, and the distortion I mentioned is the degree to which the manufacturers have achieved that goal. And the shorter the focal length, the more difficult that goal is to achieve, and thus the more expensive the lens.

And while, as pj1974 mentioned, there are software solutions to distortion, they all do so by playing with the pixels. This can fix the distortion, but at the cost of corner sharpness, and as I mentioned in my earlier post, some of these lenses already have a problem with corner sharpness without any help. This technique simply swaps one problem for another. Again as pj1974 said, distortion isn't a problem for landscape photography, it can be for architecture, but so can a lack of corner sharpness. I suspect that, for what you want to do, that is, capturing images of the inside of a cockpit, you'd have the same issues.

But you also mentioned that you'd be shooting video. If that's the primary use for this, then the reduction in resolution from still image to vide frame will mask soft corners anyway. It would only be a problem with still images.
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