Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Pana/Leica 12mm f/1.4 coming
#41
Quote:Uhmm, no. Here you are confusing your fantasy with my facts again. Yes, fantasy is written with an F.  Wink

Evidence of what? I already gave you the calculations (= evidence B) ) to show you that indeed, 12mm f1.4 on MFT is equivalent (as equivalent as things can be with different aspect ratios) to 24mm f2.8 on full frame 135 format. What more "evidence" do you require?

And you have the odd idea that it is in any sense valuable to use the same ISO number setting on different cameras. No idea why you think that is in any way meaningful.

Nor is it meaningful to use the same f-value, as the f-value stands for apparent aperture size. Which means that you oddly enough place importance of setting one camera a f/1.4 where f = 12mm and the other camera at f/1.4 where f = 24mm. So you find it meaningful/logical to set one camera at 12 / 1.4 = 8.5mm aperture, and the other at 24 / 1.4 = 17mm aperture.


Yeah, that makes so much sense. Well actually, it does not, and never has.


So, not only does the f1.4 not mean the same on the different lenses, and does for instance "ISO 100" not have an actual significant meaning or importance, you end up with very different images due to the different DOF. How interesting to keep on repeating that useless "comparison".

 

Why not compare 50mm f1.4 on MFT to 50mm f1.4 on FF? You will find that with the same ISO number setting you will get the same exposure time when using a similar exposure metering method. 

 

Or how about putting a 500mm f8 lens on a Nikon D700 at ISO 3200 and a 20mm f1.4 lens on a Nikon D5 at ISO 100. Again, similar exposure times. Now you not only have different DOF, but also different FOV!

 

It is not that hard to come up with pretty senseless comparisons  :lol:
 

 

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
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
#42
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.

Trying to guess why MFT + this 12mm f1.4 lens appears so interesting to you, while you use a big DSLR with well spaced controls. Is it just the weight? It can't be the ergonomics.

Nor the size of the lens (as pointed out, it is not really small nor light).

 

Just as curiosity remark: Easy, cheap and light way to have 18mm on the 1D mk IV is to put a EF-S 10-18mm f4.5-5.6 IS STM on it.
 

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
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
#43
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.

 

So I will continue to think "blurbing again" when you're doing your thing. Trouble is, you never ever got the point of what I was saying. And neither do you, thxbb12. Especially with a general "BC is correct" to a pretty polemic post. Disappointing.
 

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 Wink.

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
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
#44
Quote:I'm with Wim here.

 

ISO 100 on MFT is equivalent to ISO 400 on FF as far as the quality of the end result is concerned (for the same amount of pixels).

A FF camera has a 2 f-stop speed advantage over MFT - this is a baseline and it has to be taken into the equation when talking about speed equivalence. The characteristics of the end result are the only things that count in this discussion - thus field-of-view, depth-of-field and image noise.

 

Of course, a 10mm f/2.8 (MFT) has the same speed as a 20mm f/2.8 (FF) when you just look at the lens. However, a naked lens is merely good for a paperweight without a camera behind it. We are always talking about SYSTEM equivalence 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
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....
#45
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):
  • Nikon D4, Nikkor 24mm @ f/2.8, ISO 400
  • Olympus E-M1, Panasonic 12mm @ f/1.4, ISO 100
  • Fuji X-T1, Fuji 16mm @ f/1.9, ISO 300
If manufacturers where to release "slow" prime lenses for FF (say f/2.8), they would probably be smaller than equivalent MFT (f/1.4) or APS-C (f/1.9) lenses. Note that when I say equivalent here, I mean system equivalence.

 

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.

--Florent

Flickr gallery
#46
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.
#47
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.
#48
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.

#49
Quote: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.
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?
#50
Quote: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?
 

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.
  


Forum Jump:


Users browsing this thread:
1 Guest(s)