Question concerning Sigma cannon fit ultra wide lens

stephen melia

stephen melia

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Can anyone please tell me for sure if i need to or do not need to apply the 1.6 crop factor to this lens ? Sigma 10-20mm f4-5.6 EX DC HSM
as it is specially made for a cropped body as someone has pointed out ? which would make it roughly 16-32mm by my maths on a Canon cropped body if i needed to ,.
Or not as its built specially for the ultra wide to be effective which a few others have suggested 10- 22 would be not be very good for medium to large groups, however if it is 16-32 mm it could come in useful i bought it as a landscape lens as its ultra wide and had lovely results with it but shoot on a EOS 550D AND A EOS 70D
 
I don't really understand the question but...

The two lenses you mention are specifically designed for APS-C cameras like the 70D. The x1.6 crop factor just converts the field of view to 35mm terms so yes, 10-20mm on a 70D would equal 16-32mm on a 35mm equivalent camera like the Canon 5D.

Really though, maybe you shouldn't worry about crop factors as they only really help people who grew up with 35mm cameras and like thinking in those terms. It's a bit like converting 20p into 4 shillings in old money (if you're British) or converting Euros into Francs (if you're French.) It's pretty meaningless in everyday life.

If you want to go really really really wide I believe that there are a couple of wider zoom lenses, for example Sigma do a 8-16mm.
 
No i was just wandering as to whether it would be of any use for wide group shots at weddings 50 ish people or if i should just take a 24-105 for the job lighten the load
 
stephen melia said:
No i was just wandering as to whether it would be of any use for wide group shots at weddings 50 ish people or if i should just take a 24-105 for the job lighten the load
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24mm isn't very wide on an APS-C camera but I suppose it all depends on how wide the group is, and 50 ish people sound like a pretty wide group, and of course it depends on how far away you are :D

As you now have the lens maybe you can give it a try out somewhere? You may need to be careful at wide zoom settings with people close to the lens and towards the edges of the frame, you wouldn't want to make them look too distorted.
 
Was thinking of forming them around this there a 3 levels of steps here leading down to that centre in the middle should get 50 around that ok or a couple of lines of each side of the stairs bride and groom at the front
 

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Frankly I'm puzzled that you don't understand the field of view of a lens you own used on a camera you own. :thinking:

And I appreciate its a personal choice but I've never understood the purchase of the 24-105 for a crop camera, it's not wide enough for general use and just gets frustrating.

The 10-20 will do what you need.
 
Phil i only buy lenses for the full crop accept this one Sigma as i like a bit of landscape too and as i'm now about £400 squids away from purchasing a full frame,and i was told it was a waste of money to buy efs lenses if i could get EF lenses even better if they were L series if i intended going full frame as i would need to buy them again which seemed a fair point to me
,Point 2 i understand or thought i understood the field of view with my lenses but then some one i was talking too about photography told me the sigma is built specially for the crop sensor and you don't need to apply the crop factor and as i was Taking my 24 -105 with me i was just thinking Sigmas as well or not ? .I mean i thought i understood football till this year and Leicester win the league now thats a circle of confusion for you to work out ,;)
 
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stephen melia said:
Phil i only buy lenses for the full crop accept this one Sigma as i like a bit of landscape too and as i'm now about £400 squids away from purchasing a full frame,and i was told it was a waste of money to buy efs lenses if i could get EF lenses even better if they were L series if i intended going full frame as i would need to but them again which seemed a fair point to me
,Point 2 i understand or thought i understood the field of view with my lenses but then some one i was talking too about photography told me the sigma is built specially for the crop sensor and you don't need to apply the crop factor and as i was Taking my 24 -105 with me i was just thinking Sigmas as well or not ? .I mean i thought i understood football till this year and Leicester win the league now thats a circle of confusion for you to work out ,;)
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I've seen that advice a lot.
It's b****x
The problem with modern life, everyone is allowed an opinion, but that doesn't necessarily mean their opinion is valid.
Buy the lenses you need now, but buy smartly. Then when you go full frame you'll have to get new ones.
If you buy all the lenses needed for FF they don't suit your crop needs even if they fit your camera. There's no compromise to be had. People pretend there is because they don't want to think they're wasting money.
It's not a waste, buying the wrong lens is more of a waste.
50mm on 1.6 crop is s useless FL 85mm is nice, 24mm isn't wide enough to be the wide end of a zoom.
Move to FF and 24mm is plenty wide enough for most things, 50mm is useful and 85mm isn't long enough. You'll need a 135mm f2 to replace the 85
 
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Thanks for that phil nice to know and can see you know what your on about appreciated i have the 85 mm it does give a nice end product i agree .
 
As a general point I'd say that if possible it's better to buy lenses which were designed for the camera you're going to use them on and in the case of Canon aps-c cameras that would be ef-s and the aps-c specific lenses from the 3rd party boys. However, as some manufacturers don't seem to have filled all the gaps in their aps-c line up with quality lenses this may not always be the wisest move :(

Bit late now but if thinking of going ff an alternative to the aps-c wides is the Sigma 12-24mm which performs well on aps-c and ff cameras.
 
woof woof said:
Bit late now but if thinking of going ff an alternative to the aps-c wides is the Sigma 12-24mm which performs well on aps-c and ff cameras.
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Whilst it fits both, it's still 2 different lenses.
I'd agree with you that we should buy the lenses we need now.

Buying quality s/h gear makes swapping lenses fairly cost effective.
 
woof woof said:
Bit late now but if thinking of going ff an alternative to the aps-c wides is the Sigma 12-24mm which performs well on aps-c and ff cameras.
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The 12-24 is a LOT bigger and heavier than the 10-20! I've always bought FF lenses since before FF DSLRs were affordable, I still used film alongside digital, especially for wide and ultrawide shots, so it made sense for me to have all the lenses suitable for both formats. The downside is that FF lenses are by necessity bigger and heavier than Dx ones, although by using FF lenses n crop bodies, there's very little chance of vignetting.

IF a move to FF is fairly imminent (2-3 months), I would avoid buying any Dx lenses, although by doing as Phil says and buying wisely and 2nd hand, the losses on changing up to FF lenses will be reduced.
 
stephen melia said:
Phil i only buy lenses for the full crop accept this one Sigma as i like a bit of landscape too and as i'm now about £400 squids away from purchasing a full frame,and i was told it was a waste of money to buy efs lenses if i could get EF lenses even better if they were L series if i intended going full frame as i would need to buy them again which seemed a fair point to me
,Point 2 i understand or thought i understood the field of view with my lenses but then some one i was talking too about photography told me the sigma is built specially for the crop sensor and you don't need to apply the crop factor and as i was Taking my 24 -105 with me i was just thinking Sigmas as well or not ? .I mean i thought i understood football till this year and Leicester win the league now thats a circle of confusion for you to work out ,;)
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You need to apply crop factor to *all* lenses when using a cropped sensor, even specific crop only lenses. All stated focal lengths are just that, focal lengths (a 10mm EFS lens is still a 10mm lens, it's just it's designed to cover a smaller sensor area and of course had a different mount setup).

Therefore you can directly relate the field of view against all other lenses.
 
the 12to 24 sigma is 670 grams vs the 10 20 3.5 to 5.6 at 470g according to dyxum

dont think the 12-24 can take normal filters for what its worth
 
pingu666 said:
the 12to 24 sigma is 670 grams vs the 10 20 3.5 to 5.6 at 470g according to dyxum

dont think the 12-24 can take normal filters for what its worth
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Filters are a problemo... You can leave the bucket in place and then fit whatever you want but whatever you fit could well get in the way until you get to the longer end of the lenses range. The lens also takes gel filters at the camera end.

TBH I didn't buy the lens because it was FF although that did turn out to be a happy coincidence later... I bought it because I originally bought a Canon EF-S 10-22mm (I think that's what it was...) and I was very disappointed with it. I though that the Sigma was much better.

I do still question the need to relate everything to "FF." I think that for many people it just adds confusion and doubt... I do it but I used 35mm cameras for decades and find it helps but for most people I think that forgetting about crop factors might be a good idea :D
 
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woof woof said:
Filters are a problemo... You can leave the bucket in place and then fit whatever you want but whatever you fit could well get in the way until you get to the longer end of the lenses range. The lens also takes gel filters at the camera end.

TBH I didn't buy the lens because it was FF although that did turn out to be a happy coincidence later... I bought it because I originally bought a Canon EF-S 10-22mm (I think that's what it was...) and I was very disappointed with it. I though that the Sigma was much better.

I do still question the need to relate everything to "FF." I think that for many people it just adds confusion and doubt... I do it but I used 35mm cameras for decades and find it helps but for most people I think that forgetting about crop factors might be a good idea :D
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It's not that it all "relates to FF"as such, it's simply that it's the physical focal length of the lens, regardless whether it's FF or crop.

It's only compact camera lenses that give the "equivalent" FL.
 
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odd jim said:
It's not that it all "relates to FF"as such, it's simply that it's the physical focal length of the lens, regardless whether it's FF or crop.

It's only compact camera lenses that give the "equivalent" FL.
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Er, yes... but the OP specifically talks about relating lenses for use on his APS-C cameras to FF equivalent focal lengths and seems confused.

I don't see this (converting focal lengths to 35mm fov) as being particularly useful in this instance and indeed I think it just add confusion.

I can see the point of doing the math with a FF lens if you want to use it on an APS-C camera as 24mm isn't very wide on APS-C but when looking at a 10mm lens for APS-C I don't see the point in thinking "Ah Ha! This is 16mm on FF" unless you grew up with 35mm and it all therefore makes sense. I grew up with 35mm so I do the math as it helps me but for people growing up with APS-C it all seems confusing, as evidenced by the OP's post and that's not a criticism of the OP, it's like saying to someone younger than me "That Mars bar is 4 and 6." It's next to meaningless. Maybe. Possibly.
 
Well thanks for all your help and informative views i said it already once the response on two questions i put up on this forum have both been answered above and beyond what i expected. Posts on other so called forums have not come near in info or helpfulness thank you all once again, a good many in fact have been very sarcastic or condescending but hey ho found a forum that useful now nuff said.
 
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woof woof said:
You may need to be careful at wide zoom settings with people close to the lens and towards the edges of the frame, you wouldn't want to make them look too distorted.
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As Alan says, ultrawides and people's faces don't mix. Here are two pictures to explain why...

14390162291_717a940be6_b.jpg


This was taken through a Cosina Voigtlander 15mm prime on 35mm film. The man on the right and the one on the left both have their faces "pulled out" by the lens and this is an objective that's very well corrected.

On most ultrawide zooms, the effect is even more exagerated, due to the trade-offs chosen by the lens designers, as shown in the following shot, taken through a Sigma 17~35, again on 35mm film. The woman on the left of the picture is actually quite slim but she certainly doesn't appear so in this view...

15433584356_ab37fd0156_b.jpg


That is why you need to understand the pitfalls when shooting ultrawide, which is something I enjoy myself. :)
 
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