confused on wide angle lenses

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Hi

I'm a student into architecture and landscape photography and was wondering if anyone could help answer my question ??

I want to get a wide angle lens to help with the architecture shots mostly.I use a canon 450d that came with the 18 - 55mm lens. My question is, am i better off sticking to this lens, or is the 24mm /28mm lenses im lookin at better ............... I keep gettin conflicting views help !!!
 
You should probably be looking at the 10-22mm lens.

On your crop body, the 18-55 equals ~28-82mm.
 
ok I'll have a look at that one.

I'm starting to understand it better now thanks.
 
canon 10-22 or sigma 10-20, not much between them at all (and i've used both).

one thing you should know is that an ultrawide will distort the straight edges of buildings and give extreme perspectives, although this can be corrected in post-processing.
 
yeah thats the thing i was looking at *distortion* as the 24mm etc lenses have a built in feature that corrects it ...... as long as i can correct this in editing, im sure i'll pick it up.
 
"one thing you should know is that an ultrawide will distort the straight edges of buildings and give extreme perspectives, although this can be corrected in post-processing."

A well corrected wide should not distort straight lines.

As far as I remember my Canon 10-22mm didn't distort much if at all and there's no detectable distortion with my current Sigma 12-24mm.
 
Yor 450D has a (1.6) crop sensor so the 18 - 55 is effectively 29-88mm

The 24mm is suited to Full frame sensors, so to get the equivilent you would need a 15mm EF-S lens (15 x 1.6 = 24). Hope this helps :)
 
As far as I remember my Canon 10-22mm didn't distort much if at all
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well i remember clearly pointing my canon 10-22 down a street in Westminster and all the buildings on either side pointing inwards. this is ultrawide distortion and whichever one he goes for it's always going to be a problem.

here's what im talking about: (not the best pic but it demonstrates UWA distortion nicely)
3995041865_f62ffc3727.jpg
 
Here's another with the 10-22

4099618334_7828084957.jpg


I have the sigma 10-20 now and i would say it distorts more than the canon but to be honest there's not much in it. plus it's a little sharper than the canon and better built.

There's a guy on flickr who does nothing but 10 stop ND architecture shots with the sigma 10-20, i'll try and find you a link.
 
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are you talking to me or the op? he can look at charts all day long and still be none the wiser. after all, these are the kind of shots he is after - architecture. Unless he can get 100ft up in the air to avoid pointing his lens upwards he is going to get this effect in most of his shots, which is why i believe professional architecture shots are done with tilt-shift lenses.

there is a link to a guy on flickr who does some very nice B+W landscaspe and architecture shots mostly with wide angle lenses http://www.flickr.com/photos/tjintjelaar/
 
I'm correcting your comment that wide angle lenses distort straight lines. They don't. You'll get far more distortion from a standard zoom than you'll get from a good wide lens.

I'm hoping that these comments help you and the op to understand what's going on and realise that perspective is not distortion.

I hope that helps.

You're right about tilt/shift lenses but a basic understanding of what's going on is always useful too.
 
I'm correcting your comment that wide angle lenses distort straight lines. They don't.
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Thank you for correcting my comment that wide angle lenses distort straight lines. the point i was trying to get across is that an UWA lens will give a distorted perspective. I think i've made that pretty well
 
There's a lens aberration known as distortion (barrel or pincushion) and there is exagerated perspective (eg converging verticals) which is a function of close shooting distance, not the lens. Both can be corrected or modified in post processing.

If your budget will stretch to a Canon 10-22, that is the lens to get. It's excellent but like almost all zooms it suffers from a little distortion where staight lines close to the edges of the picture appear curved. There is a custom lens aberrations module in the free Raw processing software that came with your camera - Canon DPP. It's very good and will sort out distortion, and also chromatic aberration and vignetting, with a mouse click. You may need to upgrade to a newer version of DPP to get this - it's free download.

Exagerated perspective, often incorrectly called distortion, is a hallmark of all super-wides. When you tilt the camera away from dead horizontal, the sides of buildings for example converge into points.

You can correct this easily enough in post processing but you can't go too far as a) it begins to look unnatural and b) you get some loss of sharpness as what the correction does is basically enlarge some areas of the image much more than others. But used with care, both in the picture taking and in the post processing, you can get very good results.
 
Groan....

Wide angle lenses do not give a distorted perspective.

All lenses behave this way, the effect is simply more visible if you use a wide angle lens in such a way as you make it more visible.

:bang:
 
woof woof said:
"one thing you should know is that an ultrawide will distort the straight edges of buildings and give extreme perspectives, although this can be corrected in post-processing."

A well corrected wide should not distort straight lines.

As far as I remember my Canon 10-22mm didn't distort much if at all and there's no detectable distortion with my current Sigma 12-24mm.
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Unless it's a TS-E lens any wide angle will distort. Tilt/Shift or software is the only way to prevent perspective distortion on wide angles - in fact, on any lens. It's just more visible on wide angles.

People do not mean barrel distortion here, which is a completely different fact.
 
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I hope this has helped the OP :LOL:

You'd think photography was simple wouldn't you? Aperture, shutter, ISO...it should all be so easy...:naughty::)
 
Let's be clear about exagerated perspective then, aka (wrongly) as perspective distortion.

It is nothing to do with the lens, wide angle or otherwise. It is a function of distance relative to the subject. Wide angles just allow you to get closer to the subject and yet still get everything in the picture.

At more distant focus settings they behave like any other lens. Proof of this is to shoot the same subject from the same position, once with a wide angle and again with a longer lens. If you then enlarge the centre of the wide angle image to the same framing, it will be identical to the longer lens pic.

Edit: at the opposite end of the focal length range, there is the compressed perspective effect of long distance that you see with telephotos. Eg, at the start of an F1 motor race, seen from the end of the straight where they all look on top of eachother when they're actually 8m apart; or a horse race with horses galloping towards the camera from distance, they appear to be on top of eachother and running on the spot.
 
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It is indeed nothing to do with the lens and we call all prove this by making a little picture frame with our hands and looking through it. If we then tilt our little hand picture frame up and down and note what happens to vertical lines relative to the sides of our frame we will see exactly the same effect.
 
WOW !! ..... theres some info here aint there! thank you guys for commenting its defo gonna come in helpful :) i appreciate it.
 
bomberman said:
one thing you should know is that an ultrawide will distort the straight edges of buildings and give extreme perspectives, although this can be corrected in post-processing.
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I use a Sigma 12-24 on FF and it barely distorts at all. Perspective is quite exagerated (as you say, correctable in PP) but that's a fact of physics; the perspective is extremely well controlled.

To avoid the perspective exageration, you could use a tilt/shift lens and learn how to use it to suit your needs. Not a cheap option though!
 
Nod said:
I use a Sigma 12-24 on FF and it barely distorts at all. Perspective is quite exagerated (as you say, correctable in PP) but that's a fact of physics; the perspective is extremely well controlled.

To avoid the perspective exageration, you could use a tilt/shift lens and learn how to use it to suit your needs. Not a cheap option though!
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You cannot 'avoid' exagerated perspective, you can't eliminate it with any lens, not a shift lens or in post processing. You can tweak it a bit and make it look more acceptable, but not get rid of it per se.

Take converging verticals as the classic example, where the tops of tall buildings are shown smaller than the bottom. The building appears more like a pointed triangle than the square box it actually is. That's because you are much closer to the bottom, so it appears bigger than the top which is obviously much further away. Looking up at a high building, the top might be ten times further away, or more. You get the idea.

Now if you move back to a more distant viewpoint there isn't much relative difference between the distance from the top and bottom, therefore the building looks much more square.

You can do something about converging verticals by enlarging the top more than the bottom either with a shift lens or in post processing, but the relative size of the objects still remains and you can tweak things in one dimension only, and you can only go so far before it starts to look weird.

This is a picture of the famous Flat Iron Building in New York (Daniel Burnham, 1902) http://www.uncp.edu/home/rwb/flatiron-building.jpg which is interesting in a couple of ways. Because you can't get very far away from this building to take a picture, you're forced to shoot close with a wide angle. In this shot the photographer has tried to reduce converging verticals by shooting from another high building and is on a level with about the 4/5th storey.

If this was shot straight, both the top and the bottom would be smaller than the middle and my guess is that the top has been corrected with a shift lens function, and the bottom then counter corrected in the darkroom with some clever tilting of the printing paper/baseboard. The result is that the building now has parallel sides, but looks bizarre - which is the whole point of this wonderful old picture really. However, the exagerated perspective is still present in the horizontal dimension with the streets either side disappearing rapidly into the distance.

The only way to avoid these perspective effects is to shoot from a further distance.
 
HoppyUK said:
If this was shot straight, both the top and the bottom would be smaller than the middle and my guess is that the top has been corrected with a shift lens function, and the bottom then counter corrected in the darkroom with some clever tilting of the printing paper/baseboard. The result is that the building now has parallel sides, but looks bizarre - which is the whole point of this wonderful old picture really. However, the exagerated perspective is still present in the horizontal dimension with the streets either side disappearing rapidly into the distance.
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You could do parallax correction 'in camera' when you shot with a plate camera.

Gandolfi2.jpg
 
Parallax error is something different. It's the difference between two viewpoints, for example when you have a camera with a separate optical viewfinder. Normally this is not a problem but when you're shooting very close, there is a slight difference between what the viewdinder shows and what the taking lens actually sees. There are usually parallax correction marks in the viewfinder to help you frame close ups more accurately.

In the photo above, tha camera appears to be set with a degree of forward tilt on the lens, probably using the Scheimplug Rule to optimise depth of field which can be substantially increased (or at least effectively increased) for things like landscape.

You can also slide the lens up/down by slackening the brass knob near the lens, on the axis. Known as rising front or shift function, this would be what you'd use to photograph a tall building and keep the sides square.
 
HoppyUK said:
You can also slide the lens up/down by slackening the brass knob near the lens, on the axis. Known as rising front or shift function, this would be what you'd use to photograph a tall building and keep the sides square.
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You could have said that in the first place.... :wacky:
 
Voyager said:
You could have said that in the first place.... :wacky:
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It only became relevant after you posted a pic of a camera demonstating tilt function (which has nothing to do with the thread) and referred to parallax (incorrectly).
 
what's the simplest way of correcting these lens 'properties'? I have a sigma 10-20 and EF 24L. Does canon have lens profiles you can load into DPP or even a PS action? Or is it all just visual tweeking? thanks!
 
efunc said:
what's the simplest way of correcting these lens 'properties'? I have a sigma 10-20 and EF 24L. Does canon have lens profiles you can load into DPP or even a PS action? Or is it all just visual tweeking? thanks!
Click to expand...

Canon's DPP has a lens aberrations corrections suite, but only for Canon lenses. It knows what lens you've used, at what focal length and f/number (I think it may take focusing distance into account with lenses that report it) and applies custom corrections for chromatic aberration, distortion and vignetting. If your (free) version of DPP that came with the camera doesn't do it, you need to upgrade to a newer version, which is a free download.

The new version of Lightroom has a lot of similar lens corrections built in (all the Sigma range I think) plus you can create your own custom corrections by taking a specific set of images and uploading them.

DxO has something similar too, and there's a cheap but rough and ready plug-in available called PTlens.

Good review of Lightroom and demos of software lens corrections here http://www.dpreview.com/reviews/AdobeLightroom3/page6.asp

If you use Canon, DPP is the best and is dead easy. Transforms cheaper lenses into L grade :eek: (Well, kind of ;) )
 
Canon DPP is a clunky pile of poo and I'd rather use anything else, in fact, I'd rather use nothing than use DPP. YUK. :razz: Even thinking about DPP makes me want to go and wash my hands.
 
Richard, thanks for that, very interesting! DXO Optics Pro looks OK, but if I can do this in DPP, then all the better (apart from my sigma 10-20 of course). I don't know what version of DPP I have but it came with my 450D about 2 years ago. I'll wonder over to Canon's website to check. I'm sure there's probably some PS plugin for this stuff too, so maybe a bit more research required... Thanks again.
 
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