As I say in a reply to WB: I haven't noticed change of focal length when focusing. It is when changing aperture. Is that normal too?
My observation on the dust is simply based on what I see in my raw converter. I have no idea of the magnification ratio. On screen the image is about 8 x 5 inches. The test shot was shot at about 20cm. It is visible from f5,6, really disturbing from f8, horrifying at f16. I assume that it fades out when opening aperture proves that it isn't sensor dust. Tim Mostly harmless (just plain Norwegian) Never underestimate the power of stupidity in large crowds (Very freely after Arthur C. Clarke, or some other clever guy) > -----Original Message----- > From: Raimo K [mailto:[EMAIL PROTECTED] > Sent: 28. oktober 2005 22:16 > To: [email protected] > Subject: Re: My new Macro - a lemon. > > Of course it does - it´s simple geometry - when a prime lens is extended > while focusing close the focal length increases. If it were an internal > focusing zoom, it would focus close by decreasing the focal length - and > then you would be complaining that it does not have the indicated focal > length in the near range. > Those are the options, you choose. > About the dust - what magnification ratios do you use - I´d say that in > order to really show in images the dust inside the lens the magnification > must be rather extreme. > All the best! > Raimo K > Personal photography homepage at: > http://www.uusikaupunki.fi/~raikorho > > > ----- Original Message ----- > From: "Tim Øsleby" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Friday, October 28, 2005 10:32 PM > Subject: RE: My new Macro - a lemon. > > > > When saying zoom I mean that the angle of view changes. Going from open > to > > near closed, the angle narrows. I find it strange, very strange. Not > much, > > but visible. It makes me suspicious. > > > > I have made a rough test. The thing is that I having trouble finding > time > > to > > do it more properly. > > > > > > Tim > > Mostly harmless (just plain Norwegian) > > > > Never underestimate the power of stupidity in large crowds > > (Very freely after Arthur C. Clarke, or some other clever guy) > > > >> -----Original Message----- > >> From: Boris Liberman [mailto:[EMAIL PROTECTED] > >> Sent: 28. oktober 2005 19:48 > >> To: [email protected] > >> Subject: Re: My new Macro - a lemon. > >> > >> Hi! > >> > >> > The FA50/2,8 came today. Very disappointing. > >> > > >> > First, there is dust in it. Visible from 5,6 and up. > >> > Second, it behaves strangely when stepping up or down. It zooms out > >> > when > >> > going down at close range. > >> > Third, the AF is extremely poor. I could live with that, but on top > of > >> the > >> > dust and the tendency to zoom... No way. > >> > > >> > I'll give it a second try, because it was cheap. But most likely I'll > >> send > >> > the seller a mail telling him what I think about it. > >> > >> Tim, unless I misunderstand what you meant by zooming, looking here may > >> soften your concern somewhat: > >> > >> http://kmp.bdimitrov.de/lenses/primes/normal/FA50f2.8-Macro.html > >> > >> I think your macro lens should actually "zoom" when going to close > >> range... Tamron 90/2.5 of mine does something similar... > >> > >> Perhaps making a test shoot on various apertures and various distances > >> may be in order. > >> > >> Boris > >> > > > > > > > > >
