Re: M 85mm f/2
JM> But I think personal lens testing has value, especially comparisons JM> between similar focal lengths one already owns. I have owned lenses I agree completely! It is good for everyone to test his lenses in all kind of adverse conditions. Backlight with sun, backlight with white overcast sky (the _worst_ test for any lens regarding flare - sun in frame is cakes compared to huge overexposed area which affects contrast and resolution over the whole frame),... One should know his tools. Especially in photography. Only then you know what you can except, even with this new fab, the digital :) JM> In the case of the M85/2, my little tests provided some data which JM> agreed with what I already knew from actual use: the M85/2 is a JM> keeper, a nice sharp lens which is easily able to perform well in its JM> intended use as a portrait lens. Unfortunately, I have no personal experience with those fine lenses :( But a friend who is an old professional photojournalist, shooting mostly with Pentax (when he was allowed the joy of 35mm format compared to 6x6 and 6x7, publications needed the bigger ones because of issues of prepress preparation in the old days before DTP and decent scanners), did like the the M85. Best regards, Frantisek Vlcek
Re: M 85mm f/2
On Sat, 22 May 2004 07:56:52 +0200, you wrote: >JM> I used Rob's excel spreadsheet to calculate lpmm for three lenses at >JM> available apertures f2-f8: the M85/2, FA 100/2.8 Macro, and a manual >JM> focus Vivitar VS1 28-105/2.8-4 (fairly new cheap lens, not some old >JM> cult classic). > >John, you said we can flame away as we like ;-) > >So take on your azbesthos suit: > >lpm doesn't say much about any lens quality. It doesn't take into >account resolution at different contrast levels, nor does it much see >coma. Nor does it sees different gradations each lens has. > >With the high contrast resolution targets, often even cheap zooms will >perform well, but get into low contrast targets, and the lens resolves >only a muddy mush. You would have to have at least resolution targets >with several widely different contrast ratios. > >Either some difficult MTF tests, which are pretty difficult to do meaningully as >well (as always, chosing the right distance, chosing full daylight >spectrum, etc...something they don't do at Photodo), or real world >scenes... You certainly did good at chosing the right distance for >portraits, and your test does tell something about the lenses, and the >digital sensor is different enough that some great lenses can perform >badly on it, but still, you only tested for high contrast resolution. > >So your test is useful, but it doesn't tell the whole picture :) > >I am personally not in favour of lens testing. It's very hard to >evaluate properly, not subjectively, and the results are equally hard >to project into one's photographic needs. > >Best regards, > Frantisek Vlcek I agree 100% with most all your comments. Lens testing is only one limited data point when learning about a lens, and many data points are needed for a reliable evaluation. But I think personal lens testing has value, especially comparisons between similar focal lengths one already owns. I have owned lenses which time after time disappoint in some subtle manner, the kind which leave nagging doubts about the lens or my technique, when in fact some simple tests showed the lens to be totally incapable of giving decent results compared to other available lenses of similar focal length, so off goes the bad guy to the scrap heap, without regrets. In the case of the M85/2, my little tests provided some data which agreed with what I already knew from actual use: the M85/2 is a keeper, a nice sharp lens which is easily able to perform well in its intended use as a portrait lens. -- John Mustarde www.photolin.com
Re: M 85mm f/2
JM> I used Rob's excel spreadsheet to calculate lpmm for three lenses at JM> available apertures f2-f8: the M85/2, FA 100/2.8 Macro, and a manual JM> focus Vivitar VS1 28-105/2.8-4 (fairly new cheap lens, not some old JM> cult classic). John, you said we can flame away as we like ;-) So take on your azbesthos suit: lpm doesn't say much about any lens quality. It doesn't take into account resolution at different contrast levels, nor does it much see coma. Nor does it sees different gradations each lens has. With the high contrast resolution targets, often even cheap zooms will perform well, but get into low contrast targets, and the lens resolves only a muddy mush. You would have to have at least resolution targets with several widely different contrast ratios. Either some difficult MTF tests, which are pretty difficult to do meaningully as well (as always, chosing the right distance, chosing full daylight spectrum, etc...something they don't do at Photodo), or real world scenes... You certainly did good at chosing the right distance for portraits, and your test does tell something about the lenses, and the digital sensor is different enough that some great lenses can perform badly on it, but still, you only tested for high contrast resolution. So your test is useful, but it doesn't tell the whole picture :) I am personally not in favour of lens testing. It's very hard to evaluate properly, not subjectively, and the results are equally hard to project into one's photographic needs. Best regards, Frantisek Vlcek
Re: M 85mm f/2
I also like M28 3.5. I use it a lot. A. On 21 May 2004, at 03:25, [EMAIL PROTECTED] wrote: I also like the M28 3.5...
Re: M 85mm f/2
Tests speak louder than words. Good Job John. Nice to know Vic
Re: M 85mm f/2
On Thu, 20 May 2004 17:23:24 -0600, you wrote: > >- Original Message - >From: <[EMAIL PROTECTED]> > >Subject: Re: A 15mm-85F2 (was RE: 77 limited or 85* for >portraits/canndids) > > >> Portrait >> lenses don't have to be sharp!!! > >This is not to imply that the M85mm is soft, I hope. >What I don't understand is the insistence of extremes that this list >is so fond of. >The M85 may not be as sharp as the K585, for example, but this >doesn't mean it isn't a good sharp lens, it just means that the K is >sharper. >Apparently, the M 28mm suffers from the same crisis of quality. >Perhaps there are better lenses out there, but it's not like as if >the M is crap. > >William Robb The*istD and idle hands make for some easy comparisons. Please flame away all you like about how bad this is for a lens test, it pleases me, so that heck wit ya, na na na na naaa. I chose a subject distance suitable for the lens in question, i.e. 3.3 meters for the 85mm, which gives a full head-and-shoulders shot. I used Rob's excel spreadsheet to calculate lpmm for three lenses at available apertures f2-f8: the M85/2, FA 100/2.8 Macro, and a manual focus Vivitar VS1 28-105/2.8-4 (fairly new cheap lens, not some old cult classic). Shots were manually focused. I used the *istD mounted on a nice stable Ries wooden tripod, 2-sec mirror prefire, actuated by the cable release I modified from PZ to istD using PDML instructions (thanks guys). Numbers such as 0,3 show the group and pair resolved. The test target is one I keep pasted on the rec room wall for just such misadventures as this. The short story - from f2 through f4, the M 85 at 3.3 meter subject distance is the clear winner, and maintains a slight edge at f5.6 and f5. This was surprising to me, but heck I saw it with my own eyes. The 100/2.8 Macro resolves one small increment more at f8, being Group 0, Pair 6, but the spreadsheet penalizes it a bit for 100mm length vs 85mm, so the lpmm value is smaller. M85/2 2 0,3 48.9 2.8 0,3 48.9 3.5 0,3 48.9 4 0,4 54.9 5.6 0,4 54.9 8 0,5 61.6 FA 100/2.8 Macro 2 2.8 0,4 46.7 3.5 4 0,4 46.7 5.6 0,5 52.4 8 0,6 58.8 Vivitar Series 1 28-105/f2.8-4 at 105mm 2 2.8 3.5 4 0,4 46.7 5.6 0,5 52.4 8 0,5 52.4 -- John Mustarde www.photolin.com
