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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

New Fast Prime Set WOW

Michael Bravin said:
Aside from the obvious, MTF of a system is multiplicative so if the lens is 90% and the rest of the system is 50% the system is 45% so the lens MTF becomes almost irrelevant.
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heheh...conversly, if the MTF of the lens is 50% and the MTF of the sensor is 90%, then the lens MTF becomes somewhat relevant.

The thing is that at the resolutions that sensors achieve these days, it seems that it is the lens that is the limiting factor more often than not. :rolleyes5:

I'm yet to see a lens that gives anywhere near 90% MTF at limit frequency (say, 5k on S35 frame), WFO across the entire frame. You would struggle with 10% at best.

So, yes, the MTF is relevant and is the second best way to evaluate the lens short of putting one on a projector.
 
Roberto Lequeux said:
Since many are labeling the 12mm, 16mm and other wides as "physically impossible" (for FF35)... what can we safely assume from that deal?
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If one of those "many" is me, remember, I was referring to T1.4 through out the entire range. Sure, there are lenses of these focal lengths made for FF35 still cameras, but their maximum aperture is usually around F2.8 to F5.6.

Besides, those with focal length of 12mm and under have extremely short flange focal distance that will not clear the reflex mirror in a typical motion picture film camera, let alone an additional rear net mount. In the meantime, I am not sure how light coming from such a steep angle will play on a digital sensor when people seem to pursue telecentric lens design for digital cameras.
 
Interesting times indeed

Interesting times indeed

Derek Wan said:
If one of those "many" is me, remember, I was referring to T1.4 through out the entire range. Sure, there are lenses of these focal lengths made for FF35 still cameras, but their maximum aperture is usually around F2.8 to F5.6.

Besides, those with focal length of 12mm and under have extremely short flange focal distance that will not clear the reflex mirror in a typical motion picture film camera, let alone an additional rear net mount. In the meantime, I am not sure how light coming from such an adverse angle will play on a digital sensor when people seem to pursue telecentric lens design for digital cameras.
Click to expand...

As for steep incident angle and shutter clearance some form of "extreme retrofocal" design could be the answer(Dr Angenieux would be very pleased as he invented it). As far as the speed it would be an engineering marvel for sure...
 
Pawel Achtel said:
heheh...conversly, if the MTF of the lens is 50% and the MTF of the sensor is 90%, then the lens MTF becomes somewhat relevant.

The thing is that at the resolutions that sensors achieve these days, it seems that it is the lens that is the limiting factor more often than not. :rolleyes5:

I'm yet to see a lens that gives anywhere near 90% MTF at limit frequency (say, 5k on S35 frame), WFO across the entire frame. You would struggle with 10% at best.

So, yes, the MTF is relevant and is the second best way to evaluate the lens short of putting one on a projector.
Click to expand...

What sensor with an OLPF has 90% MTF?

Um...shooting a picture with the lens and camera and taking it to the finish media is a pretty good test...usually.
 
Michael Bravin said:
What sensor with an OLPF has 90% MTF?
Click to expand...

MX at 20 lp/mm

Michael Bravin said:
Um...shooting a picture with the lens and camera and taking it to the finish media is a pretty good test...usually.
Click to expand...
It is not a good test of the lens because it tests the entire path and not the lens itself. As you said, I can derive the MTF of the entire path from individual components by multiplying the MTFs of each, but I can not derive the MTF of the lens from the total. It doesn't work backwards. :frown2:

One thing I learned from measuring the MTF of Master Primes was that the MTF of the lens is important and significant in overall equation. If it is not, then why would you make sharp lenses?

I'm not trying to knock down your new lenses. To the contrary, I'm excited as hell and can't wait to play with one. I'm a big Leica fan (OK, not as big as Sanjin), but the best way to have a meaningful discussion on "how sharp is sharp" is to use industry accepted ways of measuring it.

Sensors improve every year and nearly double the resolution overnight, but not lenses. As you know, designing and building a high quality lens is difficult and physics and available materials stand in the way :mad2: When I saw the MP14mm (which interestingly is the sharpest MP in the entire range for some unexplained reason) on a projector, I was totally blown away. It seems to defy physics. And, sure enough, it performs just as well on the MTF machine, which is the best way to communicate "how sharp is sharp" and how good the lens itself actually is. It was no surprise that, when I put that lens on the camera, the images are simply breath-taking and put a big smile on my face. :beer:

So, why not spend 10 minutes and put one on an MTF machine. Seems to clear migrane instantly too... LOL
 
very active today humm michael?.. your daily stats will blow up w/ this thread.. btw.. anything on the price?
 
Jannard said:
Now, if you would just call them the "phantom lenses" for now. Oh... that's taken , too. :-)
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Hey, I like the sound of that ...

Wow Mike, I just had a chance now to check in on REDuser and boy, you sure stepped in it today, no? Have fun with that not-marketing-marketing!!
:smiley:
 
OptiTek said:
As for steep incident angle and shutter clearance some form of "extreme retrofocal" design could be the answer (Dr Angenieux would be very pleased as he invented it). As far as the speed it would be an engineering marvel for sure...
Click to expand...

Good point, thank you for reminding me.
 
Thanks, and it does say right under my forum name "REDuser sponsor." I think everyone knows were stand, and if I can't tease Mike when Jim Jannard hmself lobs it right to me, well then where's the fun in life?
 
Cool Mitch

Nice to have your technical input as always!

You have to admit Mark is right-on though :wink5:

Mitch and I kid each other because he secretly want's to be me.:scared:

Don't know why people have such an issue with it, we merely work for two competing companies LOL, but...we remain professional colleagues and friends actually.

We both believe if you cant have fun with this stuff what's the point?
 
hey mitch.. does this give you the fair answer you're looking for? ehehehehe

hey mitch.. does this give you the fair answer you're looking for? ehehehehe

Mitch Gross said:
Thanks, and it does say right under my forum name "REDuser sponsor." I think everyone knows were stand, and if I can't tease Mike when Jim Jannard hmself lobs it right to me, well then where's the fun in life?
Click to expand...
 
Pawel Achtel said:
MX at 20 lp/mm


It is not a good test of the lens because it tests the entire path and not the lens itself. As you said, I can derive the MTF of the entire path from individual components by multiplying the MTFs of each, but I can not derive the MTF of the lens from the total. It doesn't work backwards. :frown2:

One thing I learned from measuring the MTF of Master Primes was that the MTF of the lens is important and significant in overall equation. If it is not, then why would you make sharp lenses?

I'm not trying to knock down your new lenses. To the contrary, I'm excited as hell and can't wait to play with one. I'm a big Leica fan (OK, not as big as Sanjin), but the best way to have a meaningful discussion on "how sharp is sharp" is to use industry accepted ways of measuring it.

Sensors improve every year and nearly double the resolution overnight, but not lenses. As you know, designing and building a high quality lens is difficult and physics and available materials stand in the way :mad2: When I saw the MP14mm (which interestingly is the sharpest MP in the entire range for some unexplained reason) on a projector, I was totally blown away. It seems to defy physics. And, sure enough, it performs just as well on the MTF machine, which is the best way to communicate "how sharp is sharp" and how good the lens itself actually is. It was no surprise that, when I put that lens on the camera, the images are simply breath-taking and put a big smile on my face. :beer:

So, why not spend 10 minutes and put one on an MTF machine. Seems to clear migrane instantly too... LOL
Click to expand...

"For the optical designer contrast and resolution are in conflict. Increase one and you reduce the other.
Various lens makers have differing philosophies in the regard. Historically, for example,
Zeiss was reputed to design their lenses for maximum resolution, while Leica apparently tended to favour maximum contrast.
It is design decisions like these that account in part for the differing "looks" of different lens brands."

A quote from: Understanding MTF >>> The Modulation Transfer Function Explained >>>

by Michael Reichmann of Luminous-landscape.com
 
Unified focus scales

Unified focus scales

Just thinking about Unified focus scales:

My understanding of this is that different focal length lens share the same scale..?

Now how does this work with lenses of different minimum focus.. ? I ask because one of the huge time saver on set would be that when I change lens the FP doesn't have to remark our LCS disks.

If it is as simple as the wides just rotating further around (to achieve their inevitable closer focusing) then the unified scale will not translate to a remote focus unit which would be a shame.. especially considering how many jobs end up on remote focus..

All I can think is that the lenses are grouped together (12,14,18 same scale the 21,25,35 then 40,50,65, etc...)

anyone care to share the answer?

regards

Michael L
 
My understanding of Unified focus is not clear....
 
Roberto B said:
Click to expand...

That is painfully funny. I'm tempted to show it to my wife, but then again I'm afraid of the many, many possible ramifications.

Mike, I'm actively working on gaining weight, losing a lot more hair on my head and greying what's left on my beard to be all the more like you. ;-)

Mike & I do publicly kid each other when we can, and it's all part of the banter of what we do. But frankly it is an incredibly tiny, minor bit of what we do. There really is room for everybody out there, and as much as people can't believe that it all really is good-natured fun (and I'm talking about manufacturers here as well), Mike and I really do get along just fine as he says.

That's why it's so fun to tweak him.

Anyway, back to your regularly scheduled thread. Didn't mean to hijack it, just having some fun when I saw Mike in a position on REDuser that I have found myself in in the past.
 
Jim & the Mystery Primes

Jim & the Mystery Primes

Like the name of my new children's book?

Just hang on a second, I am remembering what I learned in english class about nouns and adjectives. Oh yeah, a noun can be a name, like the Mysterium and a adjective is a word that describes a noun. Like the adjective, "Mystery" and the noun "lenses". So my guess is that there is no tackness when the name is not a name but a word to describe a lens with no name. A lens with no name, I wonder what the name is? Oh yeah it is a mystery.
That is just my interpretation. I can understand how some individuals might be a bit edgy after puffing away on a good cigar and downing a few cans of Red Bull, lol.


As far as the lenses go, I guess with all things being equal to other great lenses I would pick the ones that weigh the least.:cheers2:
 
Mitch Gross said:
Didn't mean to hijack it, just having some fun when I saw Mike in a position on REDuser that I have found myself in in the past.
Click to expand...
:biggrin:
 
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