Help on buying lens with crop factor consideration...

[SkyStrike]

bro, Fisheye and a normal UWA are 2 different type of lens. If you are unsure what to get, I suggest renting first and see if you liked it. Like other seniors have mentioned, FE is not for every shot, thou it does gives you creative/nice pictures at times, but not all the time.

If you just want it wide, get a UWA, if you want a curvilinear effect, get FE. If none of these matter, I suggest you either dump it on a UWA or hold your $ till you know what you want.

 

[melthazor]

If you just want it wide, get a UWA, if you want a rectilinear effect, get FE.

I thought rectilinear is straight lens as one of the members mentioned on this thread? Curvilinear is FE?

I'm not considering fisheye because I don't like the distortion. But I thought it wouldn't be much of a fisheye because of the crop factor thus giving me a wider focal range. But thinking over now, the lens is a "semi-circle", protruding out not flat, it will still have the FE distortion.

I know the FE and wide angle lens are very different lens from each other. Just thought that by getting a smaller mm number, I can counter the crop factor thus giving me wider focal ranges. Since (I don't really know) 8mm is the smallest?

 

[Prismatic]

Ah you see, that's where I didn't know that the 10-22mm is made for cropped bodies. I read we just have to consider crop factor, even a local cam shop told me that (which isn't wrong).

It's not how wide I want it to be, I want a 10-22mm, but I don't want it ending up as a 16-35.2mm on my cam instead. And if it does become a 16-35.2mm on my cam, won't I be better off buying a 8-16mm as it would finally be 12.8-25.6mm on my cam?

But like you said, if 10-22mm is made for cropped bodies, then I still would be getting 10-22mm not more not less on my cam.

And what about sigma's 10-20mm? Same or crop factor has to be included?

Bro, if you want the 35mm equivalent of a 10-22mm on a cropped factor camera, you will need a lense of 6.25-13.75mm. As far as I know, there isn't a lenses
like that on the market. All focal lengths measurements are quoted in 35mm equivalent and not the other way round. Anyway, you shouldn't just set a target focal range
and decide that you want it to be this wide. You should really go try it out. For long focal length, 1mm diff doesn't make a lot of different. But for ultra-wides, the angle of
field differs by quite a lot even for 1mm.
Eg, the 16-35mm has a f.o.v of 98 degs
the 14mm has a f.o.v of 104 degs

Note: I think you are still confused about how they quote the focal lengths on lenses. All lenses, no matter whether they are for cropped or full-frame, are quoted
in 35mm full frame equivalent. For the 10-22mm, It's quoted like that, because you have to multiply the 1.6x crop to get an idea how wide it is as compared to a full-frame
camera. But the fact is you can't use the 10-22mm on a full-frame body (without modifications), and there isn't a 10-22mm zoom from any brand for a full-frame
camera (as far as I am aware).

 

[fmeeran]

Ah you see, that's where I didn't know that the 10-22mm is made for cropped bodies. I read we just have to consider crop factor, even a local cam shop told me that (which isn't wrong).

It's not how wide I want it to be, I want a 10-22mm, but I don't want it ending up as a 16-35.2mm on my cam instead. And if it does become a 16-35.2mm on my cam, won't I be better off buying a 8-16mm as it would finally be 12.8-25.6mm on my cam?

But like you said, if 10-22mm is made for cropped bodies, then I still would be getting 10-22mm not more not less on my cam.

And what about sigma's 10-20mm? Same or crop factor has to be included?

I think you are a bit confused.

ANY lens (crop or full frame) when mounted on any body gives the same focal length. Just that when you mount any focal length on a crop body, it shows a smaller field of view because the chip is smaller than the full frame.

So a 18mm (crop lens or full frame lens) on the 1.6x crop frame LOOKS like 18mm x 1.6 = 28mm on the full frame.

Both 10mm crop lens and 10mm full frame lens will give you the same field of view on your crop camera.

 

[fmeeran]

Bro, if you want the 35mm equivalent of a 10-22mm on a cropped factor camera, you will need a lense of 6.25-13.75mm. As far as I know, there isn't a lenses
like that on the market. All focal lengths measurements are quoted in 35mm equivalent and not the other way round. Anyway, you shouldn't just set a target focal range
and decide that you want it to be this wide. You should really go try it out. For long focal length, 1mm diff doesn't make a lot of different. But for ultra-wides, the angle of
field differs by quite a lot even for 1mm.
Eg, the 16-35mm has a f.o.v of 98 degs
the 14mm has a f.o.v of 104 degs

Note: I think you are still confused about how they quote the focal lengths on lenses. All lenses, no matter whether they are for cropped or full-frame, are quoted
in 35mm full frame equivalent. For the 10-22mm, It's quoted like that, because you have to multiply the 1.6x crop to get an idea how wide it is as compared to a full-frame
camera. But the fact is you can't use the 10-22mm on a full-frame body (without modifications), and there isn't a 10-22mm zoom from any brand for a full-frame
camera (as far as I am aware).

^ what he said.

 

[sinned79]

But the fact is you can't use the 10-22mm on a full-frame body (without modifications), and there isn't a 10-22mm zoom from any brand for a full-frame
camera (as far as I am aware).

even with modification, u can only use 12mm and above on FF for 10-22mm.

 

[melthazor]

So either way, made for my cropped body cam or not, the 10-22mm will not be 10-22mm but 16-35.2mm.

That above is what I understand, because when u said made for cropped bodies, I thought it will be 10-22mm.

Like say sigma 8-16mm, made for APS-C would have an equivalent angle of 12-24mm lens when mounted on cropped body. Isn't that range inclusive of counting in the crop factor?

So crop factor does matter when buying lens then? Because compared to the 8-16mm to the 10-22mm, seems like the 8-16mm is wider?

 

[melthazor]

I'm not saying I want something that is equivalent to 35mm.

My concern is, I don't wanna buy a lens and later realize that due to the crop factor the pictures produced on the camera is somewhat cropped smaller.

And if that is the case, a sigma 8-16mm would be a better choice because after including the crop factor, it's somewhat less zoomed in thus wider photos.

Forgive me if I'm wrong, but you guys think I want a 35mm kinda size which means I have to get a 6mm kinda lens for it (which one of you pointed out it's impossible).

And thanks to your input, I know it's clearly impossible to mount a FE, because it will always be a FE. And yes I know it's totally different from wide angle lens.

But all I really wanna know is, would the 8-16mm be wider than the 10-22mm after considering the crop factor, it is isn't it?

 

[Prismatic]

.

But all I really wanna know is, would the 8-16mm be wider than the 10-22mm after considering the crop factor, it is isn't it?

To keep it short, yes it is.

 

[melthazor]

To keep it short, yes it is.

Yes finally! All I wanted to know!

Thanks to all who replied, I learnt quite a bit.

 

[NoS77]

I guess TS totally ignore lens IQ inside the equation. Just shoot with your kit lens and determine if it's wide enough for you for now.

 

[SkyStrike]

I thought rectilinear is straight lens as one of the members mentioned on this thread? Curvilinear is FE?

my bad, wasn't thinking clearly...corrected it.

 

[melthazor]

I guess TS totally ignore lens IQ inside the equation. Just shoot with your kit lens and determine if it's wide enough for you for now.

If it was wide enough, I wouldn't even be considering wider lens...

IQ? as in image quality? I know you do get distortions, but you can't really have the best of both worlds right? Besides, many of you pointed out that there isn't such a thing as the BEST wide angle lens...

 

[NoS77]

If it was wide enough, I wouldn't even be considering wider lens...

IQ? as in image quality? I know you do get distortions, but you can't really have the best of both worlds right? Besides, many of you pointed out that there isn't such a thing as the BEST wide angle lens...

Then just get the 8-16, the widest lens available, not considering FE lens. and happy shooting.

 

[SkimMilk]

Can someone enlighten me?
Say if I got the 10-22mm dx lens, what's the dimension on a dx body? 10-22mm or do I have to multiply by the crop factor?

An FX 10-22mm lens will definitely become 15-33mm on a DX body correct?

 

[ZerocoolAstra]

Can someone enlighten me?
Say if I got the 10-22mm dx lens, what's the dimension on a dx body? 10-22mm or do I have to multiply by the crop factor?

An FX 10-22mm lens will definitely become 15-33mm on a DX body correct?

Dimension?
you mean 'field of view' ?

If you had a DX (with 10mm lens) and FX camera (with 15mm lens) side-by-side, the view through the viewfinder would cover the same angle.

hope that answers your question.

 

[SkimMilk]

Dimension?
you mean 'field of view' ?

If you had a DX (with 10mm lens) and FX camera (with 15mm lens) side-by-side, the view through the viewfinder would cover the same angle.

hope that answers your question.

Haha. Bad with technical terms.
Which means to say, even with a 10-22mm dx lens on a cropped body, I'm going to get a 15-33mm dof on an fx body. Now I understand. Thanks for the enlightenment!

 

[daredevil123]

If it was wide enough, I wouldn't even be considering wider lens...

IQ? as in image quality? I know you do get distortions, but you can't really have the best of both worlds right? Besides, many of you pointed out that there isn't such a thing as the BEST wide angle lens...

IQ is not just distortions. The wider the lens, the more it is prone to CA and blur at the edges.

And to answer all your questions:

1. Focal length is an absolute. It will never change irregardless of the type of camera body (FF or DX) is attached to it. When we talk about a APS-C camera with 1.6x crop ratio, it simply means the Field of View (FOV) of that cam is similar to that of a 35mm Full frame camera at the same focal length multiplied by a factor of 1.6. So the Field of view is different, but the focal lengths remain the same.

2. Some lenses are built to be for cropped camera use only. Canon calls this EFS, and nikon calls this DX. A EFS or DX lens of 10mm focal length is still 10mm if you mount it to a Full frame camera (assuming you can). Focal length will be the same, just that the lens is built smaller so that the image circle is not large enough to cover the sensor area of a full frame, that is why you get vignetting, where the internal of the lens is blocking light from reaching the sensor, causing an image/shadow on the edges of the picture. You probably cannot see this on Canon system since Canon do not allow EFS lenses to be mounted on their FF cams. You can see this in Nikon though, since you can mount any F mount lenses on any camera body regardless of DX or FX.

3. The widest rectilinear lens available for crop factor cam is the Sigma 8-16mm.

4. The widest rectilinear lens available for FF cam is the Sigma 12-24mm. Both lenses give approximately the same FOV when the 8-16 is mounted on a cropped sensor cam, and the 12-24 is mounted on a full frame cam.

5. A lens with a bulging front element (you refer to this as "semi-circle", protruding out not flat) does not necessary mean it will have distortion like a FE. It just simply means that the glass is bulging. Some lenses with bulging front elements but are still very rectilinear in nature are: Nikon 14-24, Tokina 16-35, Samyang 14/2.8, Nikon or Canon 14/2.8. Actually, feel free to pick up any wide angle or UWA lens and you can see that the front element is somewhat convex (bulging). The difference is just how much it bulges.

 

[daredevil123]

Haha. Bad with technical terms.
Which means to say, even with a 10-22mm dx lens on a cropped body, I'm going to get a 15-33mm dof on an fx body. Now I understand. Thanks for the enlightenment!

FOV, not DOF.

FOV = field of view, which refers to the angle of view.
DOF = Depth of Field, which refers to what is in focus.

 

[elavan]

sigma 8-16mm DC (designed for cropped body) - angle of view: 114.5 - 75.7

sigma 12-24mm DG (designed for full frame body) - angle of view: 122-84.1

even though 8mm x 1.5 = 12mm, you will not see the same "wideness" with a sigma 12-24 on 35mm full frame vs an 8-16mm on a cropped body (1.5x).