Archived posting to the Leica Users Group, 2000/11/29
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Erwin, Thanks for the enlightening answer! I am aware of the general construction pattern of zoom optics but still reckon that the 100APO uses an Elpro rather than the usual extra extension in order to maintain a long focal length at high repro ratios and keep a flat field due to the corrective rear group: I understand that the 100APO loses more focal length at close focussing settings than say the 100 Macro Elmar due to the addition of the extra group of stationary optics at the rear. Is this correct? In any case it is only of idle interest to me since I am not a big macro user. I find the 60 Macro fits my needs much better anyway! I would still like to hear from the horse's mouth though so let us know what you learn from Solms. My methods are not as rigorous as yours nor my memory so good so I am grateful to be corrected about Herr Kölsch's involvement. Maybe you could let us know where he came in design wise in the current line up? In the Canon line the old 100 EF Macro lost a lot of focal length at 1:1 and was not much different to the 50/2.5 Macro with it's close up adapter/extender which is basically a teleconverter producing a 70mm or so lens at 1:1. My experience is that the dual element close-up lenses are better at maintaining a flat field (for the lenses for which they are recommended by the manufacturer) than extension tubes and far better than single element close-up lenses. They are not as sharp as real macro lenses though and I do stop way down. Whilst I am addressing you about optics: what do you know about the Zeiss S-Orthoplanar and S-Biogon lenses as enlarging optics? I understand they are the absolute best lenses for enlargements though they were not intended for regular photography. Have you ever compared them to the best Apo Componons and Apo Rodagons, the Leica lenses or the legendary Apo El Nikkor 105mm? Just wondered at which point the difference might be noticeable... Bests Adrian - -- Adrian Bradshaw Corporate and Editorial Photography Beijing, China tel/fax +86 10 6532 5112 mobile +86 139 108 22292 e-mail apbbeijing@yahoo.com OR adrianpeterbradshaw@compuserve.com website: http://www.apbphoto.com http://www.liaisonintl.com/bradshaw.htm http://www.liaisonintl.com/bradshaw_e.htm __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com