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p.10 #3 · p.10 #3 · Apparently no pros use Sony, Fujifilm or Olympus (according to Nikon) | |
Steve Spencer wrote:
Although I totally agree this is a very small and compelling kit and it might be what a number of people want and cannot be easily duplicated by any FF 35mm system, I don't think you can really call this fast glass. In fact, most of these lenses as described have more limited shallow depth of field capabilities and light gathering when combined with the small m4/3rds sensor that at some of these focal lengths there aren't even FF lenses made with these limitations. I don't mean that as a slam on m4/3rds even though it may sound that way. If you want small, and clearly some people do, then limiting shallow depth of field and light gathering capabilities is one way to do that, and m4/3rds takes this farther than any FF 35mm system does. I just think that calling glass "fast" in this situation is highly misleading.
Now let's look at those four lenses and their depth of field capabilities. I will also assume a 4 X 3 or squarer crop which will advantage m4/3rds. That 12mm f/2 with that crop has the field of view and depth of field capabilities of a 22mm f/3.7 lens. That 17mm f/1.8 has the field of view and depth of field capabilities of a 31mm f/3.3 lens. That 25mm f/1.8 lens has the field of view and depth of field capabilities of a 46mm f/3.3 lens and that 45mm f/1.8 has the field of view and depth of field capabilities of a 83mm f/3.3 lens when comparing to FF 35mm. FF 35mm systems just don't typically make lenses with that limited of shallow depth of field capabilities and light gathering capabilities, and do keep in mind when you look at the total amount of light (which is brightness X area of the sensor) the m4/3rds sensor with the lenses you are mentioning does not have any more light hitting it than the FF 35mm sensor would with the f/3.7 and f/3.3 lenses. What I think this means is that in this comparison of m4/3rds lenses with FF 35mm you are comparing apples to oranges, or perhaps more aptly apples to a fruit that does not exist.
Note I am not saying that having such a small kit available to m4/3rds isn't a great thing to have. I think it is and if that is what you want your only choice is m4/3rds (or maybe APS-C), but let's be clear about why that is: FF 35mm systems have not chosen to make such a set of lenses with those limited capabilities. If somebody did, then a FF camera could actually get pretty close in size. To make that point, let me describe a super small alt lens kit.
Sony A7 - 416g add a battery for 450g
Voigtlander 21 f/4 - 136g
Sony FE 35 f/2.8 - 120g
Voigtlander 50 f/2.8 - 145g
Leica M 90 f/4 - 230g
Yes, you would need to add an adapter (but M to FE adapters are very light), and you should probably get the camera with the ultra thin Kolari modification to get the best performance out of the lenses. Also three out of the four are manual focus lenses, but the one AF lens weighs exactly the same as the m4/3rds counter part. If anything the fact the Voigtlander and Leica lenses are metal may overestimate their weight. I hope this illustrates that size and weight for shorter focal lengths (but not longer focal lengths--and we even start to see that here with the 90mm lens) is not determined by sensor size at least primarily, but rather by shallow depth of field/light gathering abilities. What we see when comparing m4/3rds with FF 35mm is that m4/3rds has created a niche by providing lenses that are smaller than those that are typically produced for FF 35mm, but we shouldn't pretend that they got there without any sacrifices. They got there by making lenses with some reduced capabilities, and in my view, I don't think it makes sense to call these lenses "fast." They aren't even fast by m4/3rds standards and they are very different than fast FF 35mm lenses....Show more →
Apologies for the late reply!
A very good response and technically right in most ways. And no it doesn't sound at all like you are bashing m43
Like I said in the post before, screw the depth of field comparison. If nothing else because not everybody is always looking for the most shallow depth of field they can find, sometimes, it's the opposite. DOF has become the new "megapixel or ISO" race, always looking for the most shallow and not caring about composition or subject (or the need to actually find a suitable background).
Actually, better yet, tell the depth of field as it is with those lenses. First of all, a F1.2 lens is F1.2 is F1.2 is F1.2. Always will be, always have been. It doesn't matter when sensor you put it infront or even if you have a sensor or not. DOF qualities exist in the lens as well as distance to subject and background, not in the sensor.
To put it simple, a 45mm F1.8 lens gives the depth of field of a 45mm F1.8 lens. As does the 25mm F1.8 etc. IF you want the same exact crop as on a larger sensor then yes, depth of field will be longer but if you shoot from the same distance, the DOF is the same. On the other hand, personally I like tighter crops and thus have a win win situation with m43 (getting close was always a problem for me with FF and normal non macro lenses).
As such, yes, comparisons will always be made. It may be apples to oranges, or apples to a fruit that doesn't exist or in some cases actually apples to apples in terms of picture taking machines. The comparison discussion will never be right and never wrong.
This brings us to the light gathering capabilities. While the argument of the sensor catching a quarter of the light is true it's a little dangerous argument.
It is true in every way, however, discussing it like this could lead to people thinking that an aperture of 2.8 and ISO of 200 on a camera with a larger (m43 vs 36x24mm in this example) sensor would give four times as fast shutter speeds which of course is wrong. Yes a larger sensor gathers more light as it's got a bigger surface, just like a bucket with a big opening would gather more water then a bucket with a small opening during rainfall. This is directly reflected in the ISO qualities though where a bigger sensor is superior (given the same amount of pixels on both sensors).
The problem with the kit you describe, as great at it sounds btw (would love it!) is the fact that there is only one AF lens. That lens is very small and nimble btw and a great lens. The others are pure manual focus and as such can't be taken in the discussion in the same way. Adapters are fairly cheap, and small so not much of a problem even though they do add a bit more weight and size to carry around. Still, this would make for a lovely and small kit, but still a kit that is much slower to work with then a m43 kit and AF primes and some 20%-ish heavier.
Like you said before, it's like comparing something that can't really be compared and maybe everybody should just stop comparing for the sake of our own minds?
But the discussion about the sensor gathering more light, while technically correct, is not something that is really valid and what one is after is shutter speed and this doesn't change with sensor size. ISO performance does change yes, thanks to the larger sensors ability to gather more light and thus you can push the ISO higher given the same aperture and shutter speed.
Kind Regards
Rasmus Mattsson
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