Canon ef-s 17-55mm 2.8 is usm GONE
- Thread starter Daniel 78d
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I got this lens recently for Christmas and love it. (on a T3i) I'm thinking of stepping up to a 6D, how does this lens compare to the 24-105L? Thanks!
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Loswr
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cannondale1974 said:
The 17-55/2.8 is a great lens, I used mine extensively. However, the FF equivalent is a (hypothetical) 27-88mm f/4.5, so the 24-105/4 on FF is wider, longer, and 'faster'. The only thing you're giving is activation of the f/2.8 central AF point.
The 6D/24-105 combo will deliver all-around better IQ than the T3i/17-55 combo.
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neuroanatomist said:
Why oh why are we still getting this? It's equivalent (in the terms most of us accept) to a 27-88mm f/2.8. Any statement about its 'equivalence' to an f/4.5 lens needs lots of explanation and qualification otherwise it's just mischief-making.
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Why oh why are we still getting equivalence only applying to focal length?Joey said:
It is a 17-55/2.8, regardless of the sensor size. However, if you want to see what it's equivalent of, you can't change just one side of the equation. In FF terms, the 17-55/2.8 is equivalent to a 27-88/4.5.
Just stop and think what the aperture ratio is. It's a ratio between the physical aperture and the focal length. The physical aperture at any zoom setting can't change by changing the sensor size. It's 19.64mm at full zoom, end of story. But if you want to call 55mm 88 instead, then the aperture ratio has to change.
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Loswr
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Joey said:
In fact, no.
If you'd like to make mischief, explain how f/2 on a PowerShot with a 1/1.7" sensor is equivalent to f/2 on a FF sensor. Why oh why does Canon assure us that the S100's, "...bright f/2.0 lens makes it ideal for low-light conditions or using shallow depth-of-field for dramatic, soft backgrounds??"
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Joey said:
Because it is still the truth?
If you stand next to me and we want to print (or look at on screen) the exact same image with the same noise, dof, shutter speed and framing, you with a 17-55 f2.8 on your 7D MkII and me with a FF camera, I would have to use a 27-88 f4.5 to do it.
The 24-105 f4 IS is effectively, wider, longer and faster on a ff than the 17-55 f2.8 IS is on a crop camera.
http://www.josephjamesphotography.com/equivalence/
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privatebydesign said:
To many variables.....
Framing is a fairly easy equivalent.... standing at the same spot and looking at the same object, 20mm on a crop camera will have the same field of view as 32mm on a FF camera.
Depth of field is a lot more fuzzy.... first we have to agree if we are talking depth of field as per the whole image, or if we are talking depth of field as per adjacent pixels... For example, take a 20Mpixel crop and a 20Mpixel FF camera.... The FF camera will have greater depth of field by either metric, but make it a 50Mpixel FF camera and the depth of field becomes the same if you use the "by pixel" metric...
Exposure is another fun one..... yes, FF gathers more light, but it spreads it out over a wider area. at the same aperture, the density of light per square mm is the same on either, but if we measure it by pixel, FF pixels gather more light..... unless we bring that brand new 50Mpixel FF camera in and we find out that the pixels are exposed identically to the crop pixels....
it's never as simple as we would like..... sigh....
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Don Haines said:
Well I think the fairest and most logical concept for photographic equivalence is the idea of two same sized reproductions exhibiting the same image characteristics, those being noise, dof and subject/camera motion. If you take that as a comparison, and why wouldn't you, then equivalence is a relatively simple concept.
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Nikon latest crop cameras are almost same as forum favorite Sony latest FF offerings in terms of noise. Unfortunately Nikon is kinda lazy to offer live view / video experience same as Canon/mirrosless and STM lens.StudentOfLight said:
http://www.dpreview.com/reviews/sony-alpha-7-ii/9
"In fact, in terms of ISO performance, the a7 II appears to fall near performance levels of the smaller, APS-C sensor in the Nikon D5300, showing similar noise in midtones. This somewhat nullifies the noise advantage one typically expects from larger sensor cameras, although, to be fair, it also speaks to performance increases in APS-C sensors."
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FF sensors have a 1.3 stop advantage over crop sensors on paper. There are always variables, such as the technology used in the sensor. A good example of a camera which doesn't adhere to this rule is the A7 II - even the lowly old tech Canon sensor in the 5D mk III has a one stop advantage at high ISO over this Exmor FF camera.ritholtz said:
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I'll have a go at setting out the reason for my point of view, and then I'll leave it - not going to get into a flame war.
This 'equivalence' thing can have a number of facets - exposure, depth of field, noise, field of view etc as others have stated. Some of these depend solely on the size of the sensor and the lens and nothing else influences it. Others are also affected by the pixel density of the sensor, the particular characteristics of that sensor, the processor that deals with the raw data off that sensor and maybe other factors too.
When I put a lens on a crop sensor camera after previously using a full frame camera, if I've been exposing at, say, 1/500 sec at f/2.8 and ISO 400, when I switch to the crop camera and set it to 1/500 sec at f/2.8 and ISO 400 I will expect to get a correctly exposed shot. I don't have to think "this lens on the crop camera is equivalent to an f/4.5 lens, therefore I'll have to set it to f/2.8, remember that that's really f/4.5 and use a slower shutter speed or higher ISO setting to get the correct exposure." I don't have to do that because, as far as the exposure settings I'll use is concerned, my f/2.8 lens is an f/2.8 lens whatever the size of the sensor in the camera. It is NOT equivalent for this purpose to an f/4.5 lens.
Others have argued that the noise level is higher on the crop sensor and therefore we should consider the lens to be equivalent to an f/4.5 lens, I've seen arguments here that the depth of field will be less, and that the depth of field will be greater, using a crop sensor. Noise depends on the abilties of the processor, and the pixel layout and other aspects of the design of the particular sensor in use. So it can't be stated that the noise on a crop sensor will be 1.6x higher (or 1.5x higher in the Nikon world) than on a ff sensor unless the two sensors are otherwise identical and use identical post processing - which they don't. The manufacturers tailor their cameras to get the best out of the sensor they're using.
I would rather, then, limit my concept of 'equivalence' to exposure (the aperture of the lens is primarily an exposure element, although it also affects depth of field etc) and consider all these other matters that have been argued about as separate. Thus I'm fully aware that when I use a crop sensor camera I'm going to have more trouble with image noise than I do when I use a FF camera, but I rely on Canon to keep the noise problems as low as they can within the constraints of the sensor size. Similarly I know when I'm shooting portraits on a crop camera it's going to be a bit more difficult to throw the background nicely out of focus. But I don't consider either of these issues to be related to the 'equivalence' between the two sensor sizes.
That's my two penn'orth.
This 'equivalence' thing can have a number of facets - exposure, depth of field, noise, field of view etc as others have stated. Some of these depend solely on the size of the sensor and the lens and nothing else influences it. Others are also affected by the pixel density of the sensor, the particular characteristics of that sensor, the processor that deals with the raw data off that sensor and maybe other factors too.
When I put a lens on a crop sensor camera after previously using a full frame camera, if I've been exposing at, say, 1/500 sec at f/2.8 and ISO 400, when I switch to the crop camera and set it to 1/500 sec at f/2.8 and ISO 400 I will expect to get a correctly exposed shot. I don't have to think "this lens on the crop camera is equivalent to an f/4.5 lens, therefore I'll have to set it to f/2.8, remember that that's really f/4.5 and use a slower shutter speed or higher ISO setting to get the correct exposure." I don't have to do that because, as far as the exposure settings I'll use is concerned, my f/2.8 lens is an f/2.8 lens whatever the size of the sensor in the camera. It is NOT equivalent for this purpose to an f/4.5 lens.
Others have argued that the noise level is higher on the crop sensor and therefore we should consider the lens to be equivalent to an f/4.5 lens, I've seen arguments here that the depth of field will be less, and that the depth of field will be greater, using a crop sensor. Noise depends on the abilties of the processor, and the pixel layout and other aspects of the design of the particular sensor in use. So it can't be stated that the noise on a crop sensor will be 1.6x higher (or 1.5x higher in the Nikon world) than on a ff sensor unless the two sensors are otherwise identical and use identical post processing - which they don't. The manufacturers tailor their cameras to get the best out of the sensor they're using.
I would rather, then, limit my concept of 'equivalence' to exposure (the aperture of the lens is primarily an exposure element, although it also affects depth of field etc) and consider all these other matters that have been argued about as separate. Thus I'm fully aware that when I use a crop sensor camera I'm going to have more trouble with image noise than I do when I use a FF camera, but I rely on Canon to keep the noise problems as low as they can within the constraints of the sensor size. Similarly I know when I'm shooting portraits on a crop camera it's going to be a bit more difficult to throw the background nicely out of focus. But I don't consider either of these issues to be related to the 'equivalence' between the two sensor sizes.
That's my two penn'orth.
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Loswr
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Joey said:
Sure, and 1/500 s, f/2.8, ISO 400 will give the same exposure on a PowerShot S100. Equivalent image? Not so much.
Joey said:
The aperture is an opening within the lens through which light passes, and because it's a physical opening it has a maximum diameter. That diameter, along with the focal length of the lens, is used to calculate the f/number – the ratio of focal length to aperture diameter. If you say 50mm f/2.8 is equivalent to 80mm f/2.8 on Canon APS-C, that's I ncorrect because the physical aperture isn't 'growing' from 18mm to 29mm.
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neuroanatomist said:
I don't have a full frame camera yet, but haven't I read that since the sensor is larger the light gathering ability is better compared to a crop sensor? If so, just another reason to go full frame.
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