Archived posting to the Leica Users Group, 2011/10/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi Mark. Thanks for your reply. As far as distortion correction, I know it can and is done in software, but any pixel jumping results in some loss if image sharpness. It has to as you are spreading or compressing detail to achieve less distortion. Your comments on focus shift got me thinking, so I did some tests. Between my father-in-law and I, we have a fair number of Nikon lenses. I zoomed to the widest angle and focused on an object about 7 feet away using just the central autofocus point aimed at some vertical lines of pretty good contrast. Then I zoomed in to the narrowest angle and looked at the viewfinder to check the focus, and looked at the focus ring, then pressed the button half way and watched for any refocus. They all did it. Some more than others. These were obviously very blurry through the viewfinder before the refocus. It was not so noticeable in the viewfinder with the wide angles, but I could see the difference when it refocused. Here are the lenses I used. Nikon 10-24 - a fair amount of refocus Nikon 12-24 - a fair amount of refocus. Nikon 18-200 - a very large amount of refocus. Nikon 17-55 - least amount of refocus, but noticible Nikon 18-35 - a fair amount of refocus Nikon 24-120 - a goodly amount of refocus. Nikon 70-300 - largest amount of refocus. So, I could conclude that quite a few Nikon zooms are not what was referred to as parfocal, or as you referred to as true zooms, but rather varifocal? Check yours out. You may be surprised. My broken Leica zoom is definitely parfocal as that is how I would achieve critical manual focus- zoom to 70 and focus then zoom out and recompose and shoot. I forgot to mention one more advantage of the Leica 35-70, and that is the macro mode was pretty darn good. Not 100 APO good, but on par with my Nikon 60 macro, thought not 1:1 by any means. -----Original Message----- From: Mark Rabiner Sent: Monday, October 17, 2011 10:26 PM To: Leica Users Group Subject: Re: [Leica] Report on my new 24-120/4 Nikon lens <Snip) Any distortion corrections - barrel or pincushion as well as sharpness is done as part of ones workflo which becomes more automatic every day. I get a big jerk of a move from a 24 2.8 when used closer in in software; ACR. <Snip> But if your focus shifts while zooming I'd bring it back and get another one. Because a varifocal lens is not a zoom lens. A zoom lens by nature or name stays in focus as you zoom. Other wise they call it a varifocal and charge more money. Google it and see if its a thing with the lens. If it is get a Sigma higher end. Or some other Nikon. I know they make a huge one with VR and it zooms in to 200 or something. A true all in one lens. Not my cup of tea really. -- Mark R. http://gallery.leica-users.org/v/lugalrabs/ > From: Aram Langhans <leica_r8 at hotmail.com> > Reply-To: Leica Users Group <lug at leica-users.org> > Date: Mon, 17 Oct 2011 20:49:09 -0700 > To: <leicareflex at freelists.org>, Leica Users Group <lug at > leica-users.org> > Subject: [Leica] Report on my new 24-120/4 Nikon lens > > for those who might be interested. You may remember that at the end of > August, two weeks before I was to leave on a cross country trip, I dropped > and broke my Leica R 35-70/4 zoom. I looked at a few lenses I could get > quickly as a replacement and decided on the Nikon 24-120/4 over the > 24-70/2.8 for range of coverage and lighter weight as the main priorities > I > had at the time. And Rabs said this lens was on his short list. So, here > is a report after 6 weeks of use all over the country in all kinds of > conditions. > > Advantage Nikon 24-120/F 4 > Wider angle (24 vs 35) > Greater reach (120 vs 75) > Autofocus - works better than manual on a DSLR, especially on a crop > format body (D7000) > Vibration Reduction - works pretty good > Front element does not rotate so using CPL is easier. > > Advantage Leica 35-70/F4 > Less distortion. Lightroom applies a tremendous amount of correction > to > the 24-120, and this is on a crop format body. > Much sharper a f/4 and even f/5.6 > Focus holds constant as you zoom. > Less size and weight. > Better build quality > > Having used the new 24-120 for a bit more than a month on our 6000 mile > trek > across country both ways, I have found both pluses and minuses. It is > much > heavier than my 35-70, but since it has more range I have been able to > walk > around carrying two lenses instead of four, which more than compensates > for > the added weight of the one lens. However, it does not balance as well in > my hand as the 35-70, so my keeper rate is not as high, except for the use > of VR. That is a saving feature. For that one reason I am glad I did not > get the Nikon 24-70, even though I think the 24-70 is a superior lens both > in optics and build. > > One thing that does bug me a lot is that the focus shifts as you zoom. In > shooting stills, it is not a big deal as autofocus can keep up with this. > However, I have been trying shooting some video with the D7000, and as you > zoom, the microphone picks up the lens hunting around for correct focus. > If > I shift to manual focus, the focus changes as I zoom. With the Leica, I > could focus manually and then zoom in or out w/o any focus shift so > everything would remain in focus. Not so with the 24-70, and maybe with > all > the Nikon zooms. I know my father-in-law's 18-200, 18-55/2.8, and my > other > zooms shift. Annoying. > > Then there is the large amount of distortion throughout the zoom range. > When Lightroom applies the lens correction you can really see the edges > move. Way more so than with any of the other Nikon lenses I have. Of > course, I have no lens profiles for the Leica 35-70, but I don't remember > having to apply much correction to images I have taken with it. I cannot > imagine the amount of distortion in this lens on a FF sensor. > > And the 24-120 is noticeably unsharp wide open, especially at the longer > focal lengths. Shot at 5.6 it is not that bad at the wide end, and at f/8 > is good at the tele end. The 35-70 is quite sharp wide open at all focal > lengths. Of course, it is only a 2X zoom range, so is should be sharper > and > have less overall distortion. > > So, I will keep the 24-120/4 since with VR, AF and the extended zoom it > will > have many uses when wanting to travel light, but I will ship the 35-70 > off > to Sherry when I get home in a few weeks and use it when I want the > quality > wide open or shooting things where distortion would show up and I don't > want > to correct it and loose edge detail. > > > Aram > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information