Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
Pål Jensen wrote: > > Isaac wrote: > > > It's easy, you can't change a lens' illumination angle. Coverage of a > > lens is defined by its illumination angle, not the size of the circle of > > illumination. If what you say above is true, I should be able to shoot > > 8x10 film with my SMC 50mm f1.4, and I can't... The angle of > > illumination is set by the design of the lens, along with its > > resolution, distortion, etc... The resolution of a given area inside of > > the circle of illumination, at a given size (i.e. at a given focusing > > distance) will remain constant no matter what size of film you project > > that image onto. If you change the focusing distance (increasing the > > size of the image circle), the resolution can indeed go down, but for > > other reasons involving the reproduction ratio... > > As you point out, the larger formats rarely need to have as high a > > resolution, so the designers do not put the extra expense into the > > lenses typically, but it is theoretically possible to design a lens for > > 8X10 that will have as good a "resolution" inside of 24x36 as a good > > 35mm lens. > > I certainly agree but was not exactly what I meant with my admittedly rather bad >example. When designating equal lenses (MF and 35mm) I was thinking of overall >performance. Eg the two lenses projects the same information content (total number of >lines for instance) but on circles with different size. These lenses will then have >the same resolution and be equally sharp on the finished product; eg a 8X10 print. >This what I mean with the same quality. An MF lens with the same l/mm as a 35mm >system lens can resolve a hell of lot more information in total than the 35mm system >lens simply due to the larger area of the MF lens. Or in another way, a MF lens >doesn't need the same resolving power as a 35mm lens to appear equally sharp on a >reproduction of a certain size. Right, but that's not what the thread is about... I think... We were talking about the lenses, not how much the film can resolve. If you take in the same angle of view in both 35mm and medium format, odds are that the medium format image will contain more information just because of the density of info on the bigger neg. I thought that we were talking about putting a medium format lens on a 35mm body. In that case the medium format lens will resolve the same as it ever did, just over a smaller area. > If a lens have a certain l/mm it will be constant regardless of format. But I won't >say that l/mm are equal comparable issues when comparing 35mm and MF lenses. For the >same angle of view a MF lens and a 35mm lens with the same l/mm the MF lens resolves >a hell of a lot more in finished photograph because theres a hell of a lot of more >mm's on a MF negative/positive. Hence, whats constitutes a good MF lens is something >different than whats a good 35mm lens. But not if they're both on a 35mm body... Once again, you are right about there being fewer resolution demands put onto a medium format lens (for the same amount of enlargement) when taking medium format pictures, but a lens' performance does not decrease just because you switch cameras. A lens will always perform the same weather its on a 35mm camera or medium format camera. Theoretically, if you wanted to see how your MF lens performs on 35mm, just crop out a 24x36 area from the center of your image... This is probably the core of the issue. As you say it is possible to design a LF lens to be equally good as a 35mm but I wonder if it is common or even viable on a consistent basis. No on both counts I'm afraid... I only jumped in because it sounded like you were saying that a lens' performance would somehow decrease just by switching cameras. I think we both agree that in practical terms MF optics just aren't as good over a 24x36 area... Isaac - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
On 9 Jun 2001, at 19:47, Pål Jensen wrote: > When designating equal lenses (MF and 35mm) I was thinking of overall > performance. Eg the two lenses projects the same information content (total > number of lines for instance) but on circles with different size. I think that this is where our perspectives differ, in my dialogue I was referring to the absolute LPPMM on film, ie referring to comparison of the absolute resolution a MF lens and 35mm lens of the same FL over the same area of film. I'd put the Pentax 43f1.9 LTD up against the Mamiya 7 43f4.5 (virtually symmetrical optical design) on on the same strip of film any day, and I'd say that you would have a difficult time deciding which was best (maybe the 24x65mm image would give the M7 the edge :-) By the same token I would guess that the Pentax 45mmf4 for the 67 wouldn't stand a chance up against the Pentax 43mm LTD, I found that it was far less resolute than the SMCPA50f1.2 in my testing. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://www.ozemail.com.au/~distudio/publications.html - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
On 6 Jun 2001, at 14:14, Pål Jensen wrote: > But the point in this debate is that when using a MF lens on a 35mm camera you > will actually decrease the resolution of the lens practically speaking. An MF > lens will perform worse on a 35mm camera than on a MF camera. The resolution of > the lens will of course be the same on the 35mm negative/positive as on a 24X36 > area on the MF negative/positive. However, this is not how you (normally) use > lenses. When the lens is used on a 35mm camera the image need to be magnified > much more than similar image on a MF negative/positive. Not only does this means > larger grain due to magnifications of the film but it also means magnifications > of the optical defects of the lens. Hi Pål, Sorry for my late reply, (I have actually been out making photographs :-). The absolute resolving power and minimal distortions available in some of the new generation medium format lenses (in particular the Mamiya 7 RF lenses) render them no less capable than the current prime lenses from Leica or Pentax (given optimum exposure conditions). Therefore using the centre of the image from one of these lenses should result in no less resolution (and it doesn't, by my most critical observations ie 40x magnification). The fact is that MF lenses cover a wider field of view and project a larger image circle for the same FL, there is no additional magnification over 35mm, just a larger angle of acceptance for any given MF FL. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://www.ozemail.com.au/~distudio/publications.html - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
Pål Jensen wrote: > > Isaac wrote: > > > Except the fact that the camera/lens combo would be rather awkward > > because of the larger lenses, no autofocus and stop down metering, there > > would be no compromises... Seriously though, I can't see many pros > > putting up with those limitations on a really expensive body, digital or > > no... > > I believe most of them will use it instead of a polaroid back. For these >applications (checking exposure, light setting etc) a digital slr with MF lenses >might be useful For 5 grand?!? You could buy a whole RZ setup with that kind of money. If someone needed polaroid capability, they probably didn't buy Pentax to begin with, and if they did, it would make more sense to invest in a studio camera that has a conventional polaroid (or digital) back. The price of the digital camera would have to come down significantly to make sense as a polaroid replacement... Isaac > > Pål > > - > This message is from the Pentax-Discuss Mail List. To unsubscribe, > go to http://www.pdml.net and follow the directions. Don't forget to > visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
Tom wrote: > Resolving power is not spread over the image (lenses are > essentially holographic devices). The medium format lens > simply has a wider field of view. I don't get this. I'm no optical engineer but unconceivable to me how you can double cover area without doubling optical defects as well if you use a constant area as reference (in this case 24X36). By mounting a medium format lens on a 35mm camera is basically like adding a perfect teleconverter to a 35mm system lens. Still, you get reduction of optical quality because you're magnifying optical defects as well. Say you are projecting a perfect slide with no grain etc with a certain projector lens at a certain distance to the screen. Say you choose an area within the projected image measuring 24X36 as reference. Then you move the screen farther away from the projector (and refocus) so that the image covers a larger area. You still keep the 24X36 area as reference. Wouldnt the area within the 24X36 frame now show lower resolution because you have magnified all the blemishes in the lens? This is basically what you're doing when using a medium format lens on a 35mm camera. Also, large format lenses show lower resolution than 35mm lenses. - the Minox lens has higher resolving power than 35mm system lenses. Anyway, my test results of the FA645 45/2.8 and FA645 75/2.8 clearly show that they are pretty bad when mounted on a 35mm camera. This is of course more compensated for when using them on the 645 camera because the larger area of medium format more than compensate for this. Jostein Øksne tested the A645 120/4 Macro, one of the best MF lenses made, and found that it couldn't compare at all with the M 135/3.5 (I believe it was this lens) when mounted on a 35mm slr. [My FA645 120/4 gives comparable results with the A* 135/1.8 when used on a 35mm camera, but then the FA645 120/4 Macro is an astounding lens} Pål - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
William wrote: > HUH? By that arguement, my 210mm NikkorW should only resolve > about 8 LPPM. I know for a fact it resolves closer to 60 on the > film. Format doesn't matter. Isn't 60 lines pr MM remarkably bad for a lens for the 35mm system? Pål - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
- Original Message - From: "Tom Rittenhouse" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: June 4, 2001 6:33 PM Subject: Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???) > ??? > > Resolving power is not spread over the image (lenses are > essentially holographic devices). The medium format lens > simply has a wider field of view. Older MF lenses may not > have been as highly corrected as 35 mm lenses, but in these > days of CAD/CAM the resolving power of the lenses are > essentially the same. Furthermore, the MF lens on a 35mm or > Digital camera is only using the center of the image which > tends to be sharper than the corners. There is no reason, > with modern lenses, for the MF lens to be less sharp than > the 35mm lens. I suspect that cost might be a factor. Really good lenses to cover big negatives are horrifically expensive. A Schneider Super-Symmar HM 150mm f/5.6 is over US$2800.00 at B&H Photo. I suppose this is the ultimate standard lens for 4x5. I bet it out resolves anyone's 50mm lens for 35mm. William Robb Remember, the LX Gallery is coming up. Please see: http://pug.komkon.org/LX_Gallery/LX_Submit.html for more information. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
- Original Message - From: "Pål Jensen" Subject: Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???) > Rob wrote: > > > > There is no truth in the statement the MF lenses have lower MTF values > > either, > > > Whatever resolving power a MF lens has it has to be distributed over a larger area than a 35mm lens. HUH? By that arguement, my 210mm NikkorW should only resolve about 8 LPPM. I know for a fact it resolves closer to 60 on the film. Format doesn't matter. William Robb - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
??? Resolving power is not spread over the image (lenses are essentially holographic devices). The medium format lens simply has a wider field of view. Older MF lenses may not have been as highly corrected as 35 mm lenses, but in these days of CAD/CAM the resolving power of the lenses are essentially the same. Furthermore, the MF lens on a 35mm or Digital camera is only using the center of the image which tends to be sharper than the corners. There is no reason, with modern lenses, for the MF lens to be less sharp than the 35mm lens. --Tom Pål Jensen wrote: > > Rob wrote: > > > There is no truth in the statement the MF lenses have lower MTF values > > either, > > Whatever resolving power a MF lens has it has to be distributed over a larger area >than a 35mm lens. - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
Rob wrote: > There is no truth in the statement the MF lenses have lower MTF values > either, Whatever resolving power a MF lens has it has to be distributed over a larger area than a 35mm lens. Pål - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
Re: Medium Format to 35 (WAS: Digital MZ - MR 52 projet still in the air ???)
On 4 Jun 2001, at 0:31, Pål Jensen wrote: > Todd wrote: > > > It should perform quite well, as you are just using the center of the image > > produced by the lens, which is where most lenses perorm best. > > They still show visible light fall-off at the corners at wide apertures. Also, > when used on on 35mm format all optical defects will be trippled for a certain > magnification. In addition, MF lenses are apparently harder to design well. > You'll see that almost all MF lenses have lower MTF values than comparable > lenses for the 35mm format. Even a Carl Zeiss Macro lens for the Hasselblad is > pretty average by 35mm standards. Hi Pål, My relative tests of 35mm vs MF Pentax lenses showed that the difference was negligible in all but the most demanding situations, also I noted no vignetting in the corners of the 35mm frame when using MF lenses. The distortion (colour and geometric) was very good right to the edges of the frame also. http://www.ozemail.com.au/~distudio/pentaxmfvs35mmlenstest.html There is no truth in the statement the MF lenses have lower MTF values either, just check the Photodo tests for the Mamiya 7 lenses, I have the 43, 80 and 150 and can say that they are pretty damn good irrespective of the format. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://www.ozemail.com.au/~distudio/publications.html - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
