Is there something wrong with my lens?

Glass Books

Glass Books

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Name
Sunni
Edit My Images
Yes
..........or is this how pictures taken with a wide angle lens are supposed to look? I wanted to use the lens (Sigma 10-20) for landscape pictures but haven't had a change to try that yet. Was trying it out for the first time yesterday so took some test shots like those below. Will it distort the landscapes as much as it has done these buildings? It seems to be worse at 10 and getting better at 20. Is this to be expected? :thinking:

DSC_0093.jpg



DSC_0095.jpg
 
This level of distortion is common for this particular lens, though no as bad on L series lenses, like the 17-40 f4 and 16-35 mk II.

IIRC, the distortion does become less at the 20mm end
 
nope that's exactly what you'd expect from a wide-angle lens!
you can "correct" the verticals with software, but that buggers up the edges of the picture - they go trapezoid in shape
 
Of course it's exactly as expected!

The wider the lens, the more distortion is introduced. It's therefore going to be greater at 10mm than at 20mm.

The other things to remember though is that the closer to the lens the subject is, the more the distortion is evident and the closer to the centre of the image, the less distortion is evident.

You can also remove the distortion in photoshop. It's in the filters menu. And you can use programmes such as DXO and TP Lens that will automatically process your images to remove the distortion.
 
Phew, thanks guys! At least there's nothing wrong with it, so that's good :)

AliB, thanks for the tip about positioning to reduce distortion. I'll also have a look in Photoshop filters and maybe give it a go, see how it turns out with correction.

Thanks again everyone! :thumbs:
 
Oh BTW................whispers...............your sensor needs a clean. In pic No1 above the central spire..........big blob.............that's grot on your sensor.....

Shhhhhh, it can be our secret. I'm off to clean mine in a mo, it's even worse! :)
 
here's a quick "fixup"

DSC_0093b.jpg
 
Good fix that Mike, what software?
 
Try framing the shot so something at camera height is nearer the centre. Use portrait orientation if necessary and plenty of foreground interest (or be prepared to crop).
 
Apologies for the thread hijack but what everyday materials around the house can I use to clean my sensor?? I have swabs...
 
Don't even think about it!!!

There is a filter that sits on the sensor which is actually the bit you are cleaning and it has a coating on it. Any agressive household cleaner will more likely destroy it!

Get some proper sensor cleaning products. Why on earth would you risk a costly rebuild if you damage your camera?
 
AliB said:
Don't even think about it!!!

There is a filter that sits on the sensor which is actually the bit you are cleaning and it has a coating on it. Any agressive household cleaner will more likely destroy it!

Get some proper sensor cleaning products. Why on earth would you risk a costly rebuild if you damage your camera?
Click to expand...

I wasn't just go grab some flash and be done with it.:bonk::bonk:
 
AliB said:
Oh BTW................whispers...............your sensor needs a clean. In pic No1 above the central spire..........big blob.............that's grot on your sensor.....

Shhhhhh, it can be our secret. I'm off to clean mine in a mo, it's even worse! :)
Click to expand...

Oooops! I did wonder what that was but thought I'd just got some dust on the lens.

Can I just blow it away with the rocket blower?
 
mmcp42 said:
photoshop
filter
distort
lens correction
vertical perspective

br
Mike
Click to expand...

or alternativly

View - show - grid
Select - select all
Edit - transform - Skew

You can now pull the corners out and up as much as you like.

When you finish, deselect and switch off the grid then apply a crop to the image to get rid of the bits that you have ulled out of the frame.

When you know that you will want to apply this tech to an image always look to where the verticals drop ito the bottom of the frame in your viewfinder, you will need to allow space for everything to be pulled out later.
 
It's not distortion, it is entirely normal, and you cannot correct it automatically with any software (such as PTLens).

It is exagerated perspective, created by the close viewpoint that you can get with wide lenses. It is not a lens thing as such, it is a camera to subject distance thing. Every picture will be different, which is why it can only be corrected manually. Actually, it is entirely 'correct' as it is, but it sure looks wierd with buildings that we know to be straight. It's much less of a problem with landscapes, except that trees sometimes need putting back upright ;)

Distortion is the bowing of straight lines towards the edges of the frame, and this can be corrected automatically in software that is programmed with the individual lens' characteristics.
 
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