LX7 - does its IQ compete with e.g. Sony RX100?

Started Apr 6, 2013 | Discussions
Mikedigi
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Re: LX7 - does its IQ compete with e.g. Sony RX100?
In reply to ultimitsu, Apr 7, 2013

ultimitsu wrote:

kkardster wrote:

The sensor specs favor the RX100 but the brighter and sharper LX7 lens often makes up for its lesser sensor.

This is a common misconception.

LX7 does not have a faster lens.

LX7's lens is 4.7mm F1.4, aperture is 3.6mm in diameter, actual opening is 10.2mm2

RX100's lens is 10mm F1.8, aperture is 5.6mm in diameter, actual opening is 24.6mm2

RX100's lens lets in 150% more light. it is much much brighter.

Lower light/sensor-area ratio though?

Mike

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morepix
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Major content error
In reply to Sdaniella, Apr 7, 2013

Steve D Yue wrote:

ISO 6400 [worst possible to expect on your examples]:

5DMkIII (FF) vs PowerShot G1X (1.5") vs CyberShot RX-100 (1") vs Lumix LX7 (1/1.7")

OMG! Don't you know this is an opinion forum, that actual evidence is not allowed here?! You'll be lucky not to get banned!!!

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morepix
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Trading misuse of words for misconceptions
In reply to ultimitsu, Apr 7, 2013

ultimitsu wrote:

This is a common misconception.

LX7 does not have a faster lens ... RX100's lens lets in 150% more light. it is much much brighter.

What you say is true, but that's not what most photographers (other than you, of course) mean when they say "fast" or "bright" about a lens.

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Steen Bay
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Re: LX7 - does its IQ compete with e.g. Sony RX100?
In reply to ultimitsu, Apr 7, 2013

ultimitsu wrote:

kkardster wrote:

The sensor specs favor the RX100 but the brighter and sharper LX7 lens often makes up for its lesser sensor.

This is a common misconception.

LX7 does not have a faster lens.

LX7's lens is 4.7mm F1.4, aperture is 3.6mm in diameter, actual opening is 10.2mm2

RX100's lens is 10mm F1.8, aperture is 5.6mm in diameter, actual opening is 24.6mm2

RX100's lens lets in 150% more light. it is much much brighter.

If so, then I guess that the RX100 lens is faster/brighter at the long end than it is at the wide end, because the aperture diameter at the long end is 7.6mm (37.1/4.9 = 7.6mm).

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Steen Bay
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Re: LX7 - does its IQ compete with e.g. Sony RX100?
In reply to ultimitsu, Apr 7, 2013

ultimitsu wrote:

kkardster wrote:

The sensor specs favor the RX100 but the brighter and sharper LX7 lens often makes up for its lesser sensor.

This is a common misconception.

LX7 does not have a faster lens.

LX7's lens is 4.7mm F1.4, aperture is 3.6mm in diameter, actual opening is 10.2mm2

RX100's lens is 10mm F1.8, aperture is 5.6mm in diameter, actual opening is 24.6mm2

RX100's lens lets in 150% more light. it is much much brighter.

LX7's lens is 17.7mm, f/2.3 = 7.7mm aperture diameter (at the long end)

RX100's lens is 37.1mm, f/4.9 = 7.6mm aperture diameter

So, at the long end the LX7's faster lens actually does make up for its smaller sensor when shooting in low light (because the LX7 can use a lower ISO).

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Erik Ohlson
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Re: LX7 DOES have a have a faster lens. ƒ1.4 is faster than ƒ1.8, sorry.
In reply to ultimitsu, Apr 7, 2013

ultimitsu wrote:

kkardster wrote:

The sensor specs favor the RX100 but the brighter and sharper LX7 lens often makes up for its lesser sensor.

This is a common misconception.

LX7 does not have a faster lens.

LX7's lens is 4.7mm F1.4, aperture is 3.6mm in diameter, actual opening is 10.2mm2

RX100's lens is 10mm F1.8, aperture is 5.6mm in diameter, actual opening is 24.6mm2

RX100's lens lets in 150% more light. it is much much brighter.

If the figures you give, above are the correct figures:

LX7 - ƒ1.4

RX100 - ƒ1.8

ƒ1.4 is bigger than ƒ1,8 just as ƒ2 is bigger than ƒ4.5, sorry.

Then the LX7 IS brighter. Don't get hung up on the diameter of the hole ƒ-numbers are RATIO of opening to focal length, it doesn't matter a hoot how big the 'hole' is, the aperture is a mathematical RATIO, and the bigger that number the less light is projected at that focal length.

For instance, the 6-inch diameter telescope I built from scratch (ground and polished the mirror) some 60 years ago was - yes - 6 inches in diameter ("the 'hole') but over 36 inches focal length and it worked out to about F11 "wide open".

The 200-inch diameter telescope on Mt. Wilson, 200 inches in diameter, has a prime focal length of 55.5 feet & that works out to ƒ3.3 - (same as my ZS19 ) - with that 200 inch "hole".

-Erik

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ultimitsu
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Re: LX7 DOES have a have a faster lens. ƒ1.4 is faster than ƒ1.8, sorry.
In reply to Erik Ohlson, Apr 8, 2013

Erik Ohlson wrote:

ultimitsu wrote:

kkardster wrote:

The sensor specs favor the RX100 but the brighter and sharper LX7 lens often makes up for its lesser sensor.

This is a common misconception.

LX7 does not have a faster lens.

LX7's lens is 4.7mm F1.4, aperture is 3.6mm in diameter, actual opening is 10.2mm2

RX100's lens is 10mm F1.8, aperture is 5.6mm in diameter, actual opening is 24.6mm2

RX100's lens lets in 150% more light. it is much much brighter.

If the figures you give, above are the correct figures:

LX7 - ƒ1.4

RX100 - ƒ1.8

ƒ1.4 is bigger than ƒ1,8 just as ƒ2 is bigger than ƒ4.5, sorry.

You need to be sorry indeed, because you could not be more wrong.

Don't get hung up on the diameter of the hole ƒ-numbers are RATIO of opening to focal length, it doesn't matter a hoot how big the 'hole' is,

It precisely the opposite, all that matters is the size of the hole.

the aperture is a mathematical RATIO,

No, Aperture is the size of the hole.

"in optics, an aperture is a hole or an opening through which light travels."

and the bigger that number the less light is projected at that focal length.

it is only so if FL is constant.

For instance, the 6-inch diameter telescope I built from scratch (ground and polished the mirror) some 60 years ago was - yes - 6 inches in diameter ("the 'hole') but over 36 inches focal length and it worked out to about F11 "wide open".

The 200-inch diameter telescope on Mt. Wilson, 200 inches in diameter, has a prime focal length of 55.5 feet & that works out to ƒ3.3 - (same as my ZS19 ) - with that 200 inch "hole".

your examples have no relevance to your theory, they neither support or detract it. I do not understand why you bother typing it up.

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ultimitsu
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Re: Trading misuse of words for misconceptions
In reply to morepix, Apr 8, 2013

morepix wrote:

ultimitsu wrote:

This is a common misconception.

LX7 does not have a faster lens ... RX100's lens lets in 150% more light. it is much much brighter.

What you say is true, but that's not what most photographers (other than you, of course) mean when they say "fast" or "bright" about a lens.

"F1.4 is faster than F1.8" is only completely true when you compare the same FL and the same sensor size. During the reign of 135 format it was basically a given that when you compare a F1.4 lens to a F1.8 lens, you are comparing two 135 format lenses or equal or similar FL.

The whole thing has got messy since introduction of digital sensors that come in all different sizes. you may even have seen crazy marketing claims of "XXX smart phone features a larger aperture of F2.8". well F2.8 on a 1/4 inch sensor with 2mm lens is not all that large is it?

What people need to realize is that IQ of iso 100 on one camera is not the same as iso100 on another. Between RX100 and LX7 for example, RX100's iso 280 is about the same as LX7's ISO100. For a scene were  LX7 would use F1.4  1/50s iso 100, RX100 would use F1.8 1/50s, iso 165 to get the same exposure - RX100's image would have higher quality. Or the RX100 can do F1.8, 1/80s ISO 280, it would produce the same IQ as LX7 with 2/3 stop faster shutter speed.

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ultimitsu
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Re: LX7 - does its IQ compete with e.g. Sony RX100?
In reply to Mikedigi, Apr 8, 2013

Mikedigi wrote:

ultimitsu wrote:

kkardster wrote:

The sensor specs favor the RX100 but the brighter and sharper LX7 lens often makes up for its lesser sensor.

This is a common misconception.

LX7 does not have a faster lens.

LX7's lens is 4.7mm F1.4, aperture is 3.6mm in diameter, actual opening is 10.2mm2

RX100's lens is 10mm F1.8, aperture is 5.6mm in diameter, actual opening is 24.6mm2

RX100's lens lets in 150% more light. it is much much brighter.

Lower light/sensor-area ratio though?

That is correct. But what determines IQ is not light per area, it is overall light on the whole image.

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ultimitsu
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Re: LX7 - does its IQ compete with e.g. Sony RX100?
In reply to ANAYV, Apr 8, 2013

ANAYV wrote:

ultimitsu wrote:

kkardster wrote:

The sensor specs favor the RX100 but the brighter and sharper LX7 lens often makes up for its lesser sensor.

This is a common misconception.

LX7 does not have a faster lens.

LX7's lens is 4.7mm F1.4, aperture is 3.6mm in diameter, actual opening is 10.2mm2

RX100's lens is 10mm F1.8, aperture is 5.6mm in diameter, actual opening is 24.6mm2

RX100's lens lets in 150% more light. it is much much brighter.

Yes...but shoot both and the LX7 lens will give the faster shutter speeds.

No, LX7 will give faster shutter speed if both shoot at the same "ISO". but that ISO is not comparable on the two cameras with different sensor size and high iso performance.

If you are after the same IQ, for example 9bit DR, 30 db SNR, and 18bit colour depth, then RX100 is will allow you faster shutter speed.

Faster glass as far as exposure...yes the LX7 has ' fast' glass....can't dispel this.

No it doesnt. it just has a smaller FL / aperture ratio.

Put LX7 against full frame and all other things being equal, and both a lens on FF (f1.4) will give no faster shutter speed than the LX7 @ f1.4. Exposure is the same

But what do you mean by all other things being equal? is expected final image quality being equal? if so then FF can afford over 20 times faster shutter speed than LX7.

so one can use the LX7 full wide open, and keep iso lower than say a camera with f2.8

that would make the other camera use 2 stops higher iso, and can add more noise and NR smearing (if shooting jpeg).

Not if the other camera's iso400 is better than LX7's iso100 and iso800 is better than LX7's iso200.

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morepix
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Oh, thanks for the "education" ...?
In reply to ultimitsu, Apr 8, 2013

Oh. Thanks for the "education" ... ???

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ultimitsu
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Re: Oh, thanks for the "education" ...?
In reply to morepix, Apr 8, 2013

morepix wrote:

Oh. Thanks for the "education" ... ???

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David
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You are welcome, and this one was on the house.

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fotophool
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Erik: RX100 @ 6400 ISO
In reply to Erik Ohlson, Apr 8, 2013

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Erik Ohlson
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Re: Oh, thanks for the "education" ...?
In reply to ultimitsu, Apr 8, 2013

Ultimitsu.

I'm sorry, you are the one who needs education.

Aperture is a RATIO. Fact, not opinion, even on Nikon dSLRs, end of discussion.

And, no, I'm not going to bother with further attempts to educate you as you seem to "Know everything" -smirk-

-Erik

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ultimitsu
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Re: Oh, thanks for the "education" ...?
In reply to Erik Ohlson, Apr 8, 2013

Erik Ohlson wrote:

Ultimitsu.

I'm sorry,

Apology accepted, but your understanding is still lacking.

you are the one who needs education.

Don't we all? you just need it a bit more than everyone else.

Aperture is a RATIO.

LOL

Fact,

Citation?

not opinion,

If you dont think your view qualify then well...

even on Nikon dSLRs,

DSLRs do not have aperture, whether a ratio or a diameter.

end of discussion.

Arent you having fun? I am having fun.

And, no, I'm not going to bother with further attempts to educate you as you seem to "Know everything" -smirk-

Since I am the (allegedly) know-it-all and you cannot get your head around what aperture is after 10 posts, any education from your way would serve no utility. I think you concession is wise.

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Erik Ohlson
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Re: Erik: RX100 @ 6400 ISO
In reply to fotophool, Apr 8, 2013

Lovely image Photophool, as I have come to expect from you.

I'll readily concede a great image at ISO 6400, and a pretty quick shutter speed, too.

Thanks for the 'education'  

But not my cup of tea with it's lame zoom, which may seem too harsh a word, but that's my take on it - YMMV.

When they give it at least a 10x zoom, I may well be interested.

-Erik

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AndyW17
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Re: Oh, thanks for the "education" ...?
In reply to ultimitsu, Apr 8, 2013

ultimitsu wrote:

Erik Ohlson wrote:

Ultimitsu.

I'm sorry,

Apology accepted, but your understanding is still lacking.

you are the one who needs education.

Don't we all? you just need it a bit more than everyone else.

Aperture is a RATIO.

LOL

Fact,

Citation?

not opinion,

If you dont think your view qualify then well...

even on Nikon dSLRs,

DSLRs do not have aperture, whether a ratio or a diameter.

end of discussion.

Arent you having fun? I am having fun.

And, no, I'm not going to bother with further attempts to educate you as you seem to "Know everything" -smirk-

Since I am the (allegedly) know-it-all and you cannot get your head around what aperture is after 10 posts, any education from your way would serve no utility. I think you concession is wise.

What's up with the tone here, Ultimitsu?  The folks on this part of DPR tend to be cooperative and friendly.  Whether or not you or the other poster(s) are in agreement, or need to discuss further to build understanding, there's no need for ad hominem attacks.  Please.

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Markr041
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Re: LX7 - does its IQ compete with e.g. Sony RX100?
In reply to Erik Ohlson, Apr 8, 2013

Erik Ohlson wrote:

Markr041 wrote:

Erik Ohlson wrote:

Markr041 wrote:

Erik Ohlson wrote:

Sean Nelson wrote:

Erik Ohlson wrote:

Interestingly, both of these wider-aperture cameras, LX7 & S-100 have built-in ND filters so one can shoot wide open in daylight without severely over-exposing. Seems backwards to me. 

You obviously don't shoot many videos where an ND filter is needed to get lower shutter speeds in bright light.   People who are serious about video really love the camera for it's built-in ND filter.

Yes, "People who are serious about video!"

This category doesn't include me - I shoot video maybe once a year "whether I need to or not".

It's nice that you guys have the ND for that, but the same thing applies: aperture too large for daylight. And I hardly shoot stuff that can't take a higher ISO in "Low light', either 

And I have topaz DeNoiser for that.

SO. We're on different tracks. Cool.

-Erik

There are reasons, apart from video, to shoot wide open in bright light, :

- to play with shallower dof, when upping the shutter is not enough to achieve the correct exposure

-  to use a slow shutter (water falls) without having to close down the aperture and thereby lower the quality.

Really?

Actually, with these tiny focal length lenses (actual, not "equivalent") the DOF effects are negligible.

Don't take my word for it, Ming Thien is famous for his camera reviews and says in regard to LX7:

http://blog.mingthein.com/2013/03/25/leica-d-lux-6-panasonic-lx7/#more-5339

I actually advocate shooting at lears as wide as ƒ4.5 to minimize the diffraction effects that you may get in pursuing "DOF", which these small lenses have "in spades' anyway.

Please see this thread for more, and more detail on my findings:

http://www.dpreview.com/forums/post/51182438

I DID shoot a waterfall, once, with film & an ND. 

-Erik

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"Actually, with these tiny focal length lenses (actual, not "equivalent") the DOF effects are negligible."

Really?  I do not have to rely on authorities, I have the camera. And there is a lot you can do with dof.

Here are some examples (if you do not like them, that is fine, but they show playing with dof):

And, at full telephoto (such as it is) and wide open, the dof is shallower on the LX7 than on the RX100. Look it up.

Mark, this no valid comparison.

Trying to increase DOF with aperture is countered by deleterious diffraction.

I never said that the small lens had INFINITE DOF, as you seem to be trying to prove.

-Erik

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I am not comparing anything; I am showing that you can achieve nice dof effects with the LX7, which you seem to say is not possible. What you actually said was they were "negligible". Which is an overstatement, to be kind. And diffraction occurs at small apertures, not wide open. So I do not understand what you are saying - you get shallower dof at wide not small apertures. And you have recommended, correctly, avoiding small apertures anyway. Do you have an LX7?

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ultimitsu
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Re: Oh, thanks for the "education" ...?
In reply to AndyW17, Apr 8, 2013

AndyW17 wrote:

What's up with the tone here, Ultimitsu?  The folks on this part of DPR tend to be cooperative and friendly.  Whether or not you or the other poster(s) are in agreement, or need to discuss further to build understanding, there's no need for ad hominem attacks.  Please.

We are not in complete disagreement. I agree that discussion should be civilised, proper and friendly.  We do however have slightly different view on what constitute a discussion.

Mr Ohlson's post which begin with "I'm sorry, you are the one who needs education" was a response to a reasoned post by myself - I explained why he was wrong and I cited a source proving my point. Mr Ohlson's post on the other hand was not written in a good spirit for discussion. That post contained no substance and does not further the discussion, instead it was a snide and arrogant bait for flame. If Mr Ohlson had nothing substantial to say, he should have said nothing, otherwise it would only attract responses such as the one in question.

So please, Mr Andy, I would encourage you to direct your annoyance to Mr Ohlson.

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Cyril Catt
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Re: LX7 - does its IQ compete with e.g. Sony RX100?
In reply to Erik Ohlson, Apr 8, 2013

Erik Ohlson wrote:

Markr041 wrote:

Erik Ohlson wrote:

Markr041 wrote:

There are reasons, apart from video, to shoot wide open in bright light, :

- to play with shallower dof, when upping the shutter is not enough to achieve the correct exposure [...]

Really?

Actually, with these tiny focal length lenses (actual, not "equivalent") the DOF effects are negligible. [...]

-Erik

"Actually, with these tiny focal length lenses (actual, not "equivalent") the DOF effects are negligible."

Really?  I do not have to rely on authorities, I have the camera. And there is a lot you can do with dof.

Here are some examples (if you do not like them, that is fine, but they show playing with dof):

And, at full telephoto (such as it is) and wide open, the dof is shallower on the LX7 than on the RX100. Look it up.

[...]Trying to increase DOF with aperture is countered by deleterious diffraction.[...]

-Erik

Erik, Markr041 seems to have left this discussion, but I think he was trying to show a decrease in DOF, not an increase.

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