Pana/Leica 12mm f/1.4 coming - Printable Version +- Opticallimits (https://forum.opticallimits.com) +-- Forum: Forums (https://forum.opticallimits.com/forumdisplay.php?fid=4) +--- Forum: Micro-Four-Thirds (https://forum.opticallimits.com/forumdisplay.php?fid=16) +--- Thread: Pana/Leica 12mm f/1.4 coming (/showthread.php?tid=762) |
Pana/Leica 12mm f/1.4 coming - wim - 06-15-2016 Quote:Uhmm, no. Here you are confusing your fantasy with my facts again. Yes, fantasy is written with an F. Actually aperture is just about the relation between light outside the camera ("F/1") and how much it lets through, not taking glass surface etc. losses into account. Therefore, f/1.4 is F/1.4 with any lens, FL is totally immaterial in this regard. A specific f-stop just means that it let's a specific light ratio pass through the lens, compared to the light outside. Becuase of the way a lens images the outside world, this happens to be directly related to the FL, diameter wise, but that is immaterial. It still lets through the same amount of light per area unit. That is what the f-stop number is about. Regards, Wim Pana/Leica 12mm f/1.4 coming - wim - 06-15-2016 Quote:You don't get more light on MFT at f1.4 than f2.8 on FF, though... And ISO can be set to whatever the situation asks for. You actually get the same amount of light per area unit, that is what aperture and iso are about, whether you use FF or APS-C, 4/3 or any other format. Genrally speaking, and F/1.4 lens is useful becuase you can use a lower iso, and get less noise, or limit DoF, same reasons as always. And weight is indeed about ergonomics. Personally, I have a FF dslr, and a 4/3 camera, both with a few lenses. For exactly that reason: weight and size. And 4/3 cameras have become really good. Regards, Wim Pana/Leica 12mm f/1.4 coming - wim - 06-15-2016 Quote:I never said anything else than f/1.4 remains f/1.4, no matter which sensor behind. It leads at equivalent lenses nonetheless to the same shutter time, at given ISO and same lighting / exposure method. BC, I have no idea from what you get your idea of 12 and 24 mm lenses, none of them as used in the comparison. But reading superficially is enough for someone who already owns his truth. Yep, F/1.4 is F/1.4, no matter what the lens (FL) or the sensor size. DoF may be different, for sure, but that is also the case with wideangles vs teles at the same f-stop . Essentially, the shorter the FL, the deeper DoF is at the same f-stop, and it is more or less linear - this is why at a 2x linearly smaller sensor the DoF is twice as deep with an FL equivalent lens: it is twice as short, FL-wise. Kind regards, Wim Pana/Leica 12mm f/1.4 coming - wim - 06-15-2016 Quote:I'm with Wim here. Hi Klaus, Maybe one addition: it looks these days that pixel count, up to a certain point anyway (which we have not reached yet with 4/3 and larger sensors), is no longer all that important: with smaller pixels you get more noise, but averaged out over a sensor area it is about the same with the current state of sensors. In short, it is just the sensor size that therefore appears to affect image noise, due to the magnification required. Obviously, this is an approximation or an average, and one can pixelpeep and measure to the n-th degree, but that is more or less what it amounts to, based on some of the stuff I have been reading lately. Kind regards, Wim Pana/Leica 12mm f/1.4 coming - thxbb12 - 06-15-2016 System equivalence: it's very simple really. As Klaus mentioned it's about the system (lens + camera). These 3 systems and settings will give you equivalent results (same FOV, same noise, and same DOF):
Likewise, a FF system with a 24-70 f/2.8 lens would be equivalent to a 12-35 f/1.4 in MFT land. Such a lens would be huge and very costly. The smaller the sensor size, the less it makes sense to produce very fast lenses (from a cost and size perspective). I find APS-C to be a fairly good comprise between DOF capability, size and cost. MFT is very interesting for very long lenses and macro. Pana/Leica 12mm f/1.4 coming - chrismiller - 06-15-2016 The pixel pitch of apc is approaching mft, so I'm not sure there is much tele advantages - 24Mpix 80d ~ 15.3Mpix mft. Also I'm not sure there are many(any?) mft tele lenses that can take full advantage of the 20Mpix sensors at the long end. Pana/Leica 12mm f/1.4 coming - Klaus - 06-15-2016 I think there's a simple way to explain this. Take a MFT camera and a FF camera. Let's assume that the whole sensor surface is sensitive to light. The sensitivity per square mm is identical. Do not attach a lens. Same lighting conditions. Open the shutter for -say- 1/100sec on both cameras. Now "count" the photons that have been "gathered" by both sensors. Which one gathered more photons and by which factor ? Note: number of photons = speed. Pana/Leica 12mm f/1.4 coming - Brightcolours - 06-16-2016 Equivalent focal lengths are not the same focal lengths. They merely are focal lengths which give the same FOV. Equivalent f-values are the same aperture sizes. They give the same DOF. Equivalent ISO-settings are not the same ISO number, they merely give the same total light to form the image and result in similar exposure times. How are ISO settings in digital decided upon by a manufacturer for a camera model? With a known light intensity, they take the whole sensor output in JPEG form with a chosen tonal curve and are free to choose a point on the resulting tonality curve which they deem appropriate, and call that for instance "ISO 400". They actually look at the whole sensor output. Image noise does not count in this discussion, although it is a happy side effect. Why do I say that? We are not trying to get the same noise per camera, we are trying to get the same DOF and FOV in the first place. Only if somehow exposure time is somehow important (for instance, to freeze motion, or avoid camera shake), similar exposure times may also come into play. That is where equivalent ISO settings come into play. Do we ever look for same noise results? No, we actually do not. It would be a silly mess, having to set things differently on a Nikon D300 than on a Nikon D70 or a Nikon D500, and never ending up with the same exposure time. The happy coincidence of similar noise only occurs with sensors of more or less the same generation, using more or less similar technology. Recap: Equivalent ISO settings are primarily about just one thing: trying to get similar exposure times. ISO settings are determined by the whole sensor output, not a square mm of it. Equivalent ISO settings result in the same amount of light captured by the sensor. Only with same generation, same technology sensors, equivalent ISO settings result in similar noise. If the sensors happen to have the same MP count, equivalent ISO settings result in similar amount of light captured per pixel. Pana/Leica 12mm f/1.4 coming - Brightcolours - 06-16-2016 Quote:I think there's a simple way to explain this.Do you assume that the whole surface is sensitive to light, AND that the sensitivity per square mm is identical? Then the FF sensor has captured about 4 times more photons. Was this your point? Pana/Leica 12mm f/1.4 coming - Klaus - 06-16-2016 Quote:Do you assume that the whole surface is sensitive to light, AND that the sensitivity per square mm is identical? This explanation targeted the ISO discussion (ISO 100 (MFT) is not identical to ISO 100 (FF)). It wasn't directed to you if you understood that already. :-) A problem with the linear discussion stream. |