[Brightcolours]

What he wrote is actually correct. The RX100 III has a ~24-70mm f4.8-8.0 135 format "full frame" equivalent lens.

If you want to compare APS-C and/or MFT standard kit zoom lenses, then also look at what it is equivalent to.

Lets take your 12-50mm f3.5-6.3 example as... example  :lol: :

12 x 2 = 24, 50 x 2 = 100, 3.5 x 2 = 7, 6.3 x 2 = 12.6. 

Is a 24-70mmm f4.5-8 lens faster than a 24-100mm f7-12.6 lens? I think so.

 

Another example. Lets take an APS-C kit lens, the Canon EF-S 18-55mm f3.5-5.6 IS STM.

18 x 1.6 = 28.8, 55 x 1.6 = 88, 3.5 x 1.6 = 5.6, 5.6 x 1.6 = 9

So, also true. A 24-70mm f4.5-8 lens is faster than a 29-88mm f5.6-9 lens.

You can speak utter crap but that does not make it true. One of the slower u4/3 kit zoom is the 12-50 which is f3.5-6.3 for 24-100 range. Nearly all kit lenses I am famiiliar with for u4/3/aspc are faster than f8 at the long end (in addition to having a much larger sensor). No clue how you can claim this is 'slower' than 4.8-8.0 but I'm sure there is some methodology to your claim. What is valid is that for a 'slow' lens you do get compactness but that doesn't make it any faster. Your graph below is also not relevant as it is not comparing this camera 'effective' speed to APS or u4/3. Rather it is comparison with cameras with similar or much smaller sensors (what pisses me off is that you make this claim; provide a graph that 'seems' to support your claim but it is totally irrelevant.

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I grant you that this camera is very compact; and a selection of people will find it 'good enough' in some situations (just look at the number of people using 'cell phone' camera but that does not make this a miracle beast with regards to light gathering or sensor ability in low light (low here is relative and with an f8 lens low doesn't have to be 'very' low to be an issue). Conversely this camera should be noticeable improvement on cell phones and given its size the cellphone crowd might find it quite useful.

[dave9t5]

Watch the toilet language dude.

 

That chart is full-frame equivalent.

 

Your μ4/3 12-50 is f/7-f/12.6 equivalent.  That's the methodology that both dpreview used in that chart and that these guys use in their review: http://www.opticallimits.com/m43/827-olympus1250f3563ez

<p style="margin-left:40px;">Specifications

<p style="margin-left:40px;">Equiv. focal length 24-100 mm (full format equivalent)

<p style="margin-left:40px;">Equiv. aperture f/7-f/12.6 (full format equivalent, in terms of depth-of-field)

 

Basic MATH "claims" that:

<p style="margin-left:40px;">f/7 is a smaller number than f/4.8

<p style="margin-left:40px;">f/12.6 is a smaller number than f/8

 

Therefore an equivalent basis math "claims" the RX100 III lens has superior equivalent aperture opening (i.e. faster gathering of light) than this particular μ4/3 zoom.

 

 

 

You can speak utter crap but that does not make it true. One of the slower u4/3 kit zoom is the 12-50 which is f3.5-6.3 for 24-100 range. Nearly all kit lenses I am famiiliar with for u4/3/aspc are faster than f8 at the long end (in addition to having a much larger sensor). No clue how you can claim this is 'slower' than 4.8-8.0 but I'm sure there is some methodology to your claim. What is valid is that for a 'slow' lens you do get compactness but that doesn't make it any faster. Your graph below is also not relevant as it is not comparing this camera 'effective' speed to APS or u4/3. Rather it is comparison with cameras with similar or much smaller sensors (what pisses me off is that you make this claim; provide a graph that 'seems' to support your claim but it is totally irrelevant.

-

I grant you that this camera is very compact; and a selection of people will find it 'good enough' in some situations (just look at the number of people using 'cell phone' camera but that does not make this a miracle beast with regards to light gathering or sensor ability in low light (low here is relative and with an f8 lens low doesn't have to be 'very' low to be an issue). Conversely this camera should be noticeable improvement on cell phones and given its size the cellphone crowd might find it quite useful.

[Guest]

Ok.  My erorr but you wrote bullshit text. The lens is 24-70f1.8-f2.8. Most site  that talk about 'equivalent' do not adjust the f-stop. As an example:

http://www.dpreview.com/previews/sony-cy...c-rx100-m3

-No were do we see f8 mentioned.T

The 'equivalence' in focal length is used to so people can understand the perspective provided by the lens. Doing the same with the aperture (imho; though I'm 100% sure brightcolour will disagree) is excessively misleading.

--

Why do you describe it as an f8 lens when ti is f2.8 ? Anyways I stand by my statement that the graph you provided has no relevance to the conversation as none of the camera are aspc or u4/3. But I will admit my misunderstanding that your calling it an f8 lens when it was really a f2.8 lens. Yes I know brightcolours love to adjust aperture on the lens all the time but I think he is a unique case.

[Brightcolours]

Ok.  My erorr but you wrote bullshit text. The lens is 24-70f1.8-f2.8. Most site  that talk about 'equivalent' do not adjust the f-stop. As an example:

http://www.dpreview.com/previews/sony-cy...c-rx100-m3

-No were do we see f8 mentioned.T

The 'equivalence' in focal length is used to so people can understand the perspective provided by the lens. Doing the same with the aperture (imho; though I'm 100% sure brightcolour will disagree) is excessively misleading.

--

Why do you describe it as an f8 lens when ti is f2.8 ? Anyways I stand by my statement that the graph you provided has no relevance to the conversation as none of the camera are aspc or u4/3. But I will admit my misunderstanding that your calling it an f8 lens when it was really a f2.8 lens. Yes I know brightcolours love to adjust aperture on the lens all the time but I think he is a unique case.

Nothing misleading about it. You just don't understand it, but that does not make it misleading at all.

 

Why does one describe a lens as  70mm when it is 25.7mm? Same thing!

What does the f-number stand for? Focal length divided by the number, gives aperture size.

 

So, the lens is in fact, at the long end, f=25.7mm with max aperture of f/2.8 = ~9.18mm

It is EQUIVALENT to a 70mm lens on 135 film format (commonly referred to in the digital SLR age as "full frame").

Aperture, of course, does not change. It still has a max. aperture of 9.18mm.

Max. f-value then: 70 / 9.18 = f7.63

 

You will have the same angle of the cone of light being captured, you will have the same size of hole letting the light through, you will have the same DOF, everything pretty much similar.

 

It just is that simple. You can also get those numbers by just multiplying by crop factor and not bother with calculating aperture size.

 

Lens equivalence (both focal length and f-stop) is an accepted theory just based on the physics and laws of optics and light, and has been understood by photographers for many decades, especially photographers who dealt with different formats. Of course, in the internet forum age there will always be forum members who don't understand the simple principles and will always try to discredit stuff.

 

Anyway, if one wants to educate oneself on the matter:

http://www.josephjamesphotography.com/equivalence/

http://www.luminous-landscape.com/essays...nses.shtml

http://www.pointsinfocus.com/tools/depth...st=10&u=us

 

Excessively explained.

[Sylvain]

Ok.  My erorr but you wrote bullshit text. The lens is 24-70f1.8-f2.8. Most site  that talk about 'equivalent' do not adjust the f-stop. As an example:

http://www.dpreview.com/previews/sony-cy...c-rx100-m3

-No were do we see f8 mentioned.T

The 'equivalence' in focal length is used to so people can understand the perspective provided by the lens. Doing the same with the aperture (imho; though I'm 100% sure brightcolour will disagree) is excessively misleading.

--

Why do you describe it as an f8 lens when ti is f2.8 ? Anyways I stand by my statement that the graph you provided has no relevance to the conversation as none of the camera are aspc or u4/3. But I will admit my misunderstanding that your calling it an f8 lens when it was really a f2.8 lens. Yes I know brightcolours love to adjust aperture on the lens all the time but I think he is a unique case.

The dpreview graph just supports the idea of DOF control., which is often lacking from compact, hence the graph to show why it's an interesting camera. The rest about "fast" "slow" etc is irrelevant in this graph and in this context.