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Nokton 25/0.95 samples

Jonas

Active member
Jonas, a lot of things you posted there, I disagree with. I will not go into the details as you have not used any such fast lenses and I have not had a chance to use the Nokton either.

I would simply disagree with that quoted statement. I would answer affirmatively on both counts: the system is great (compared to Sony which can not handle such fast lenses) and the lens also appears to be fine.
Vivek, I'm not surprised at all. And, a many things look strange when taken out of context. I'm sure we can both agree and disagree about a lot of things, not only about this lens.

And you are right, the fastest lens I have used regularely was an f/1.1 lens, then there are several f/1.2 lenses I have owned and used for longer times. Now, are you saying I'll get vertigo when comparing this 25/0.95 to a 50/2 on a FF camera?
 
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Vivek

Guest
Now, are you saying I'll get vertigo when comparing this 25/0.95 to a 50/2 on a FF camera?
An f/0.95 lens is very different than an f/1.1 lens which is very different than an f/2 lens- in terms of use. For starters, metering will be very different due to sheer amount of light that comes through the lens.

The argument that a 25 f/1 lens on m4/3rds is "equivalent" to a 50mm f/2 lens on a 35mm full frame is wrong. I have used such lenses on both the formats to say so.

If this does not fit well with the theories, I would ask you to try for yourself.:)
 

Jonas

Active member
An f/0.95 lens is very different than an f/1.1 lens which is very different than an f/2 lens- in terms of use. For starters, metering will be very different due to sheer amount of light that comes through the lens.

The argument that a 25 f/1 lens on m4/3rds is "equivalent" to a 50mm f/2 lens on a 35mm full frame is wrong. I have used such lenses on both the formats to say so.

If this does not fit well with the theories, I would ask you to try for yourself.:)
From 1.1 to 0.95 (f, not T) may be around 0,4 stops. In theory. If that makes metering very different I'll either do fine or find myself in big troubles. Maybe we here have the first lens ever that doesn't fit the equivalence theories for normal photographing, and there is no need to ask me to try it, I have already said I'll buy the lens and evaluate it for a longer period.

Vivek, sometimes I don't know what to think about your posts. To avoid further disagreements for now I'll just switch to read only mode for a while.
 
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Vivek

Guest

Untitled by Vivek Iyer, on Flickr

50/0.95 on NEX (details of areas in focus get mushed up- problem with the NEX sensor). The lens did not "become" a 75mm f/1.5 "equivalent" (and it never will).

What would the use of the same 50/0.95 on a G1 make it an equivalent of? 100mm f/2?!

I have a 98mm f/1 lens that covers 6x6cm. Does it "become" slower when used on smaller format cameras?

Heck, no.
 

M5-Guy

New member
:lecture:

The ONLY "Equivalent" would be what f/stop would be needed to achieve the same DOF, NOT light gathering power.

A 25mm f/.95 for a m4/3 shoot at f/.95 on a m4/3 camera will have the same DOF as a 50mm f/1.5 on a FF camera...BUT it still has the light gathering power of f/.95, even though the DOF is deeper BECAUSE OF the sensor size.
The senor size affects DOF, not light gathering power...

Oh, please, let's get past this already!
f/2 on a m4/3 lens, lets in the same light gathering power as a f/2 on a FF camera, or a 6x6 camera or a 4x5 camera... what changes is the f/stop needed to have the same DOF across the formats at any given distance.

That is the precise reason the f/stop method was developed. The formula used makes sure that regardless of the focal length, the iris opening is proportional to the focal length. fl/stop = opening size, 100mm/4 = 25mm, that is: f/4 = a 25mm opening. on a 300mm lens, f/4 = a 75mm opening. Yes it is 3x the size of the 100 f/4, BUT, it lets in THE SAME amount of light. With different formats, though, f/4 will have different DOF depths, controlled by the format (Film/sensor) size.
 

M5-Guy

New member

Untitled by Vivek Iyer, on Flickr

50/0.95 on NEX (details of areas in focus get mushed up- problem with the NEX sensor). The lens did not "become" a 75mm f/1.5 "equivalent" (and it never will).

What would the use of the same 50/0.95 on a G1 make it an equivalent of? 100mm f/2?!

I have a 98mm f/1 lens that covers 6x6cm. Does it "become" slower when used on smaller format cameras?

Heck, no.
Lovely portrait...
Beautiful color and mood
 

Bob

Administrator
Staff member
:lecture:

The ONLY "Equivalent" would be what f/stop would be needed to achieve the same DOF, NOT light gathering power.

A 25mm f/.95 for a m4/3 shoot at f/.95 on a m4/3 camera will have the same DOF as a 50mm f/1.5 on a FF camera...BUT it still has the light gathering power of f/.95, even though the DOF is deeper BECAUSE OF the sensor size.
The senor size affects DOF, not light gathering power...

Oh, please, let's get past this already!
f/2 on a m4/3 lens, lets in the same light gathering power as a f/2 on a FF camera, or a 6x6 camera or a 4x5 camera... what changes is the f/stop needed to have the same DOF across the formats at any given distance.

That is the precise reason the f/stop method was developed. The formula used makes sure that regardless of the focal length, the iris opening is proportional to the focal length. fl/stop = opening size, 100mm/4 = 25mm, that is: f/4 = a 25mm opening. on a 300mm lens, f/4 = a 75mm opening. Yes it is 3x the size of the 100 f/4, BUT, it lets in THE SAME amount of light. With different formats, though, f/4 will have different DOF depths, controlled by the format (Film/sensor) size.
DOF discussions are never complete without circle of confusion specifications. Lately I am given more to the circle of confusion about 1.4-2x inter-pixel dimension (for bayer sensors).
So you see, you can't even determine equivalence until you have determined the rest of the imaging system and then to what use the resulting image will be put, such as what print size and viewing distance.
With the 1.4-2x inter pixel spacing rule of thumb at least I am not defining my dof by print size, but by print size capability.
So really, equivalence is very tough to define.
thanks
-bob
 

M5-Guy

New member
:lecture:

The ONLY "Equivalent" would be what f/stop would be needed to achieve the same DOF, NOT light gathering power.

A 25mm f/.95 for a m4/3 shoot at f/.95 on a m4/3 camera will have the same DOF as a 50mm f/1.5 on a FF camera...BUT it still has the light gathering power of f/.95, even though the DOF is deeper BECAUSE OF the sensor size.
The senor size affects DOF, not light gathering power...

Oh, please, let's get past this already!
f/2 on a m4/3 lens, lets in the same light gathering power as a f/2 on a FF camera, or a 6x6 camera or a 4x5 camera... what changes is the f/stop needed to have the same DOF across the formats at any given distance.

That is the precise reason the f/stop method was developed. The formula used makes sure that regardless of the focal length, the iris opening is proportional to the focal length. fl/stop = opening size, 100mm/4 = 25mm, that is: f/4 = a 25mm opening. on a 300mm lens, f/4 = a 75mm opening. Yes it is 3x the size of the 100 f/4, BUT, it lets in THE SAME amount of light. With different formats, though, f/4 will have different DOF depths, controlled by the format (Film/sensor) size.
DOF discussions are never complete without circle of confusion specifications. Lately I am given more to the circle of confusion about 1.4-2x inter-pixel dimension (for bayer sensors).
So you see, you can't even determine equivalence until you have determined the rest of the imaging system and then to what use the resulting image will be put, such as what print size and viewing distance.
With the 1.4-2x inter pixel spacing rule of thumb at least I am not defining my dof by print size, but by print size capability.
So really, equivalence is very tough to define.
thanks
-bob
There is a lot of areas to think about for sure, I agree. I just get so tired of the DOF/equivalence vs f/stop, and all the misunderstanding with it. :deadhorse:

I tried to explained it layman terms, I am no mathematician, nor do I know all the variables (as you and others may know), But, I try to keep things simple, so, as a practical guide, it may help someone understand this property. We never had this "Problem" in the film days... and I guess pre-internet days either. Maybe because there was not a internet to have open discussions.

Thanks for reply :)
 

Jonas

Active member
DOF discussions are never complete without circle of confusion specifications. (...)
So really, equivalence is very tough to define.
Aren't the CoC-sizes used by, for example, DOF-master OK for the discussion? I don't care about the exact values maybe but the relation between the different sizes of the CoC should be clear; 4/3 CoC needs to be half of the FF CoC to achieve the same resolution as I understand it.

But, I'm interested in learning more if needed for taking part in a discussion.

I have for example always assumed that people are talking about a common situation and goal when discussing equivalence, for example; the same motif, the same vantage point, the same print size as the end result and as a sidenote an agreement about not thinking about the differences in aspect of ratio. That seems complicated and simple enough for me. Is there anything here I have got wrong please let me know.


50/0.95 on NEX (details of areas in focus get mushed up- problem with the NEX sensor). The lens did not "become" a 75mm f/1.5 "equivalent" (and it never will).

What would the use of the same 50/0.95 on a G1 make it an equivalent of? 100mm f/2?!
A lens never becomes anything. How could it? We should be able to agree a lens is what it is no matter what adapter you put it on.

I have a 98mm f/1 lens that covers 6x6cm. Does it "become" slower when used on smaller format cameras?

Heck, no.
Really, why do ask/mention this? My guess is that you are very much aware about how the FOV changes when moving a lens between cameras with different sensor sizes. Right?
I'm also pretty sure you know, and very well so, how the DOF is changed by the fact that you use different aperture sizes and take the images at different shooting distances. Right?

Then what are you arguing about?

If you want to discuss the differences in image quality and lens rendering styles between super fast lenses and medium slow lenses for a bigger format then we can do that. I started above when first posting about my impressions from the Nokton 25/0.95 samples.

I have owned FF cameras, 1.5, 1.6 and 2x crop cameras. I have done experiments and I have found the theories to work out surprisingly well in real life. Just saying.

:lecture:

The ONLY "Equivalent" would be what f/stop would be needed to achieve the same DOF, NOT light gathering power.

A 25mm f/.95 for a m4/3 shoot at f/.95 on a m4/3 camera will have the same DOF as a 50mm f/1.5 on a FF camera...BUT it still has the light gathering power of f/.95, even though the DOF is deeper BECAUSE OF the sensor size.
The senor size affects DOF, not light gathering power...
(...)
f/2 on a m4/3 lens, lets in the same light gathering power as a f/2 on a FF camera, or a 6x6 camera or a 4x5 camera... what changes is the f/stop needed to have the same DOF across the formats at any given distance.

That is the precise reason the f/stop method was developed. The formula used makes sure that regardless of the focal length, the iris opening is proportional to the focal length. fl/stop = opening size, 100mm/4 = 25mm, that is: f/4 = a 25mm opening. on a 300mm lens, f/4 = a 75mm opening. Yes it is 3x the size of the 100 f/4, BUT, it lets in THE SAME amount of light. With different formats, though, f/4 will have different DOF depths, controlled by the format (Film/sensor) size.
I would say DOF is what is interesting in these discussions. For the hard core equivalence enthusiasts "light gathering power" is important as they are interested in not only DOF but also noise. So they don't say the light gathering is the same between a µ4/3 25/1 and a FF 50/2 lens/camera combo. Using the same f-stops will make the lenses let in the same amount of light per area unit, not per image. And surely the f-stop method was developed for exposure reasons, not for DOF comparisons?

So, discussing DOF only here, and for the sake of convenience I'll round 0.95 to 1, OK?...
M5-Guy, how did you get f/1 equiv to f/1.5? In these discussions one usually multiply with the crop factor and finds a 25/1 lens is equiv to a 50/2 lens with regards to DOF. What's the reason for multiplying with a factor of 1.5?

Oh, and yes, I get bored by all this as well but I want it to be right now that people are here.

/Jonas
 

Jonas

Active member
(...) So, either our system is a poor system, or the Nokton is a poor lens.
Surely my claim above, from post #11, can be taken as a base for an adult discussion about system differences?

The Nokton is not a poor lens. Our systems are also not poor. So what is it I had in mind stating the above?

Well, when looking at the N25 samples the second and third time it hit me that we can't achieve the same results using our cameras and available lenses (N25 included) as any FF camera user with nearly any 50/2 lens mounted can.

The night image of the the ship is a possible exception, it depends on the exact lens used. The other images demonstrate more CA. more LoCA and uglier bokeh (subjective of course) and probably lesser resolution than I got with my 5D with any of my 50mm lenses used at the equiv f-stop.

What is the big drama here?

Anyone having used a decent medium fast normal lens on a FF camera should be able to see that. Anyone not being a blind system fan should be able to discuss it. Maybe not wanting to discuss it but being able to.

/Jonas
 
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Vivek

Guest
For the hard core equivalence enthusiasts "light gathering power" is important as they are interested in not only DOF but also noise. So they don't say the light gathering is the same between a µ4/3 25/1 and a FF 50/2 lens/camera combo. Using the same f-stops will make the lenses let in the same amount of light per area unit, not per image. And surely the f-stop method was developed for exposure reasons, not for DOF comparisons?
They are not the same. If you believe they are, this Cosina lens is totally insanely priced as you can get a "much faster" 50mm lens plus a 35mm full frame DSLR for the same price of this lens and a suitable camera.
 

Jonas

Active member
"They are not the same."
Vivek, I don't understand exactly what you are replying to here.

If the price is insane or not, well, it seems as folks here are going to buy it so the price is probably not totally insane. In this case the novelty and portability comes at a price. That price can be spelled IQ plus money.
 
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Vivek

Guest
Jonas, If the unit is a pixel then they aren't the same and hence the f stops come in handy while making the exposure.

One can always find a way to argue themselves into believing somethings about DOF, f-stops (or "equivalents"), etc. But the reality may not be the same while tripping the shutter.

You asked earlier if the price (Cosina 25/0.95) is OK?

I am saying that if you believe it to be a 50/2 "equivalent" on a 35mm full frame (which it is not) then the price is insane, not withstanding any novelty or portability.

For both (novel/portable), try the NEX-5. How useful it will be to you would be the price you would be paying to use it.:)
 

Jonas

Active member
Jonas, If the unit is a pixel then they aren't the same and hence the f stops come in handy while making the exposure.

One can always find a way to argue themselves into believing somethings about DOF, f-stops (or "equivalents"), etc. But the reality may not be the same while tripping the shutter.
Yes, you have found you way it seems. My experience (G1, 5D, 5DMkII) is different. Well, when the N25 becomes available I'll see the magic for myself.

You asked earlier if the price (Cosina 25/0.95) is OK?

I am saying that if you believe it to be a 50/2 "equivalent" on a 35mm full frame (which it is not) then the price is insane, not withstanding any novelty or portability.

For both (novel/portable), try the NEX-5. How useful it will be to you would be the price you would be paying to use it.:)
You may be surprised about the equivalence thing, so may I.
A NEX is of no interest to me. For me the price would be too high. Different personal opinions is nothing new.

So, when I buy the N25 I'm paying an insane price as I know equiv theories actually work? OK then, so be it. I already mentioned I have decided for µ4/3 and take what I can get,

I notice you are avoiding several of the questions asked earlier, you are just repeating "it is not the same" - something we already know.

All this started with me talking about performance at the same FOV and DOF. Remember; "Well, when looking at the N25 samples the second and third time it hit me that we can't achieve the same results using our cameras and available lenses (N25 included) as any FF camera user with nearly any 50/2 lens mounted can." What in the N25 samples suggests anything else?

/Jonas
 

LCT

Member
Interesting thanks. Great to get some shallow DoF with those half frame cameras. Those 25/0.95 pics look like 50/2 FF ones actually with harsher OOF than a good Summicron though.
 

M5-Guy

New member
My Light-meter must be off....

I Just took a photo with my G1 and adapted Zeiss 50mm f/1.5 C-Sonnar... ISO 100, f/1.5, @ 1/60 sec (2x Crop), Camera on "Aperture Priority" mode.

I then put the lens on my Leica M5 (TTL metering), at ISO 100, f/1.5, 1/60 sec... (FF) the 2 meter needles crossed paths as needed for a proper exposure...

Maybe I have a bad lens. The exposure was the same, :wtf: :confused: :eek: :shocked: :ROTFL:
I thought for sure that the G1 would need to adjust the shutter to 1/15 sec for a proper exposure with some of the mis-understanding I am reading. :rolleyes:

I'm done here....good luck Vivek
 
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Jonas

Active member
So, discussing DOF only here, and for the sake of convenience I'll round 0.95 to 1, OK?...
M5-Guy, how did you get f/1 equiv to f/1.5? In these discussions one usually multiply with the crop factor and finds a 25/1 lens is equiv to a 50/2 lens with regards to DOF. What's the reason for multiplying with a factor of 1.5?
My Light-meter must be off....
I wish you could have replied to the only thing I asked about. In case it was just a mistake on your part and my question hence was offending, well, I'm sorry.

I also notice now that I read my post again that the sentence starting with "So they don't say the light gathering is the same..." was sloppily written and can be taken wrong. But the sentence following should that one should clear it up.

All that about your light-meter and so on... I don't know what to say.
 

LCT

Member
Whatever value one chooses for FF CoC, the latter will always be 2 times larger than FT's for the simple reason that the diagonal of FF sensors is 2 times longer than that of FT cameras. Then at full aperture, a 25/1 FT lens has merely the same DoF as a 50/2 FF one. Suffice it to check with any DoF formula. Works with any camera, film and sensor format IMHO.
 

Owen_Coors

New member
Thanks for that explanation of the cropped sensor effect on bokeh, LCT. There are still some cropped sensor subjects that I don't understand, like: on a 25mm lens, on m4/3 camera, will the background compression still be that of a 25mm even though the FOV is magnified x2 (50mm?)
 

Jonas

Active member
(...) There are still some cropped sensor subjects that I don't understand, like: on a 25mm lens, on m4/3 camera, will the background compression still be that of a 25mm even though the FOV is magnified x2 (50mm?)
A µ4/3 image taken with at 25/2 will look exactly like a FF image taken at 50/4 (naturalmente disregarding the aspect of ratio difference, noise difference and assuming optically identically performing lenses and the same vantage point).

/Jonas
 
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