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chris_tribble

M9 - some more reliable news?

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I must say, if the M9 doesn't need filters . . . I won't be using them. I hear the argument for using UV filters because it's cheaper than a new front element . . . . . . but if I add up all the UV filters I haven't bought (and, let's face it, they aren't cheap), then it would pay for quite a few new front elements!

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I must say, if the M9 doesn't need filters . . . I won't be using them.

 

Me too.

 

The only person I know that regretted not having a UV filter fitted is our Andy Barton, who lost a 19mm R lens through unrepairable sand damage to the front element.

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Me too.

 

The only person I know that regretted not having a UV filter fitted is our Andy Barton, who lost a 19mm R lens through unrepairable sand damage to the front element.

 

It's like all insurance. I've just had a hard drive go on an imac about 6 weeks after it's out of warranty - £170 for a nice new much faster drive. That's actually less than the extended warranty for the machine . . . If I then add in all the extended warranties I haven't bought for all our other machines . . . and their predecessors, I'm still thousands in the black.

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It's like all insurance. I've just had a hard drive go on an imac about 6 weeks after it's out of warranty - £170 for a nice new much faster drive. That's actually less than the extended warranty for the machine . . . If I then add in all the extended warranties I haven't bought for all our other machines . . . and their predecessors, I'm still thousands in the black.

 

Quite. I never buy extended warranty on anything. It will either fail within the warranty period, particularly if electronic, or it will last beyond the period over which I have amortised the purchase in my mind. If it fails early, that's my look-out, and I'll deal with it at the time. Like other respondents I only use filters for specific effect - black and white, particularly, or for protection in particularly inimical environments.

 

Regards,

 

Bill

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Every lens I have ever owned has had its front glass protected by a UV filter, which is much cheaper to replace than any lens work. Now I just use a UV/IR filter ...so what is the big deal? Do people use their lenses without filters on M7 for example.?

 

I have to be very careful when using my 35 Summilux at night, especially shooting into areas where there are street lights or other bright sources of light. With a filter on, I get reverse reflecions at times. Taking off that filter eliminates the problem, and it really is an issue for me as I try to shoot at deep dusk or later.

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some say they get none at 35 mm

 

I call anybody who doesn't see cyan vignetting on the M8 with a 35mm lens half-blind. Turn off lens detection, and shoot an even colored subject with a summilux wide open. On full-frame the results would be unacceptable by "Leica standards."

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I call anybody who doesn't see cyan vignetting on the M8 with a 35mm lens half-blind. Turn off lens detection, and shoot an even colored subject with a summilux wide open. On full-frame the results would be unacceptable by "Leica standards."

 

Well, the discussion was wether you get cyan drift in the corners if you use IR filters on other cameras than the M8....

 

 

___

To speak before you think is like wiping your ass before you shit.

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If Leica doesn't announce an M9 on 09/09/09 the rumors of an M10 on 10/10/10 can start then we have a whole year to speculate and advise.

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RE: UV/IR filters: I have a recent video camera (JVC) and it definitely shows a touch of IR contamination in colors (purple blues, a hint of red in blacks) and would probably benefit from an external filter. Silicon is IR-sensitive - regardless of what filtering is in the camera, an external filter will block additional IR.

 

Yes, IR filters will cause some degree of cyan drift in corners with a wide-angle lens on any camera, including film. Because the wider the field of view, the more light near the edge of the field of view is traveling through the filter slantwise, making the filter effectively thicker and stronger, and thus starting to cut into the visible red wavelengths.

 

E.G. a lens with a 90-degree FoV will be looking "sideways" at 45 degrees on each side. Geometry shows that the effective filter thickness for the edges will be sqrt-2 thicker, or 1.4x as much filtering effect as in the center.

 

It is easy to see this with an IR filter. Take it off the lens, and look through it at a white surface. Now rotate the filter until you are seeing it edge-on. As it rotates, it will become progressively cyan/greener as seen through at an angle. This will affect any imaging material, film or silicon, that is sensitive to visible red light - just as a regular green filter would.

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I call anybody who doesn't see cyan vignetting on the M8 with a 35mm lens half-blind

 

In that case I must be half blind. This is the full frame from an uncoded 35mm pre-ASPH Summilux, with filter, shot at f1.4 or f2. Although my M8 had lens detection switched on, no correction was done as the camera doesn't know the lens that's mounted - in the Exif data the focal length field is blank.

 

Not a great photograph, but I think it illustrates the point that cyan corners are not always going to occur with every 35mm lens.

 

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John, none whatsoever apart from minor curves tweak - though I'm prepared to post the untweaked version if this version is deemed to be unacceptable.

 

You are correct about the glow. It illustrates one of the characteristics of the original 35mm Summilux when used wide open rather well <grin>

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Also, as I posted in another 09/09 thread, a very big day for Beatles fans. Release of the remasters (in mono and stereo) of all the original UK albums, as well as the release of The Beatles Rock Band game.

 

Jeff.

 

Cool on the release of the Beatles remasters - that's really good news!

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Not a great photograph, but I think it illustrates the point that cyan corners are not always going to occur with every 35mm lens.

 

I am not saying that the cyan drift is always objectionable, but it definitely there in many situations. And why should this be different with another camera if you use UV/IR filters.

 

Here is an example shot with the 35mm summilux aspherical wide open in very cool daylight late in the day. Does anyone on here not see the cyan drift in the corners?

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Is it only a co-incidence that Apple also have a rumoured event on September 9th? Will the M9 feature a built-in iPhone? Might it have built-in WiFi and thus be the iM9? (With a direct connection to Leica Support.) Even more alarmingly, rumour has it that September 9th will be a Wednesday!

"direct connection to Leica Support" isn't that an oxymoron or something like one.

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Stuns and Bernd - now THAT is an interesting comparison (and yes I see cyan corners in the 35 Summilux ASPH shot, and no I don't in the 35 pre-ASPH shot).

 

Let me toss out a weird theory in several parts, relating to how optical design may be interacting with IR light and the filters.

 

1) The pre-ASPH 35 'lux is one of Leica's most cyan lenses to begin with - this is from my own shooting experience on film, and from the lens color chart in E. Puts' Leica M lenses - Their Soul and Secrets, in which the pre-ASPH is shown to be 4 points more cyan and 1 point more green than the ASPH (ISO CCI values). Is it possible that the pre-ASPH lens is already cutting into the visible red wavelengths to such an extent that the additional, marginal effect of the IR filter is washed out - i.e., whatever visible red the filter blocks is already blocked across the whole image anyway by the lens itself, leaving little or no differential between the corners and the center?

 

2) Many of the ASPH designs from Solms occasionally show hot spots in the center - separate from vignetting. I believe others have reported the 28 'cron shows a specific IR hot spot. IMHO the 75 'cron shows a white-light hot spot at times. Could the 35 f/1.4 ASPH have a IR hot-spot problem?

 

3) Finally, and this may be related to the hot spot question, the 35 'lux ASPH has a strong concavely-curved rear element, which will have the tendency to act as a mirror lens and reflect a semifocused image of the image on the sensor back to the sensor. Given the bright pink clothing in the middle of Bernd's image, is that adding even more diffuse pink tint to the center, making the red/cyan differential between the center and the corners more marked than usual?

 

This has been a growing concern for me as I have experimented with the ASPH lenses, especially those with concave elements on or near the back of the design. Leica has shown genius in pushing lens performance by using new formulas, many of which replace the traditional double-gauss design's convex rear elements with concave ones (50 f/1.4 ASPH, 75 f/2 APO-ASPH, 35 ASPHs f/2 and f/1.4,). But I'm not sure that this is a good design change if the lens is going to sit in front of a highly reflective sensor instead of matte film.

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It may very well be that the aspherics accentuate the problem. As you may know, the aspherical version can't be coded, or at least not professionally, and it is such a beauty that I don't want to mess with it. I actually corrected this particular picture later for coding. I also think that the color temperature of the light at that time, together with the even colored wall made it more pronounced. But if you look at Sean's tests, Cyan drift is pretty noticeable with any 35mm lens, especially wide open. A lot of times, the subject matter hides it.

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