Ho provato a cercare ma non trovo notizie su questo obiettivo; qualcuno di voi lo conosce o conosce siti dive poter leggere qualcosa in merito?

Grazie
Gian

Vai su Google. Digita sigma 180mm. Premi Enter: 381.000 voci trovate in un secondo.
Se il tuo obiettivo esiste, hai trovato quanto t'interessa.

Pare che esista. Ho trovato un 180/2.8 apo macro. E' lui?

Come scritto avevo già provato a cercare ma i risultati sono praticamente tutti della versione f3,5 del 2,8 con Google non si trova nulla di significativo.
Esiste certamente ed è la versione APO Macro. A me interessa sapere se qualcuno ne conosce le qualità, se ne ha, o sa indicarmi siti dove è stato provato.
Grazie comunque
Gian

Ecco tre pareri:

1.
The first thing you notice about the lens is that it has Sigma's black Zen finish. The Zen finish was intended to give a nice texture to the lens when holding it. And for the most part it succeeds. However, with the nice feel comes a price - it's hard to wipe clean and marks easily. The Zen finish grabs on to cleaning cloth every chance it gets making it hard to wip effectively. The Zen finish also marks due to the rubber used in the finish.

The second thing you notice is the weight (or mass) of the lens. This is a lens where you will need muscles to carry around. You have to remember that no-one said that glass is light. The build quality is excellent. I have the utmost confidence that I can use the lens to take out a would be burglar and be able to mount the lens on my D200 to take their picture.

How does it perform on a camera?

Well, it breaks down into a couple of categories:
* Viewfinder - being a f/2.8 lens, the viewfinder is bright and clear.
* Balance on Camera - on a Nikon D200, it's great. Good balance, and easy to hold. Just be careful with the focusing ring. Being a screwdriver lens, the focusing ring moves when the lens focuses. Therefore, you will need to keep your hands clear of the ring so that it can focus smoothly. Luckily, the lens is large enough for this to happen.
* Hand hold abililty - Normally, an 180mm lens would require a shutter speed of a least 1/180 of a second according to the rule of thumb. On a DSLR like the D200, you should require at least 1/270 of a second due to the smaller APS-C size sensor. Luckily, the size and the shape of the lens makes it every easy to hand hold. I was able to get acceptable results down to 1/80 of second.
* Image quality - the reason to buy the lens. It's sharp - not just in the center but corner to corner.
* Colour - Excellent. Looking at close ups, I did not see any CA.
* Flaring - may be there but I couldn't see any

Miscellaneous points:
a. 9 blade apperature for smooth boken
b. small tripod mount - not removeable
c. Metal lens hood that is threaded
d. Internal Focus - good for filters
e. slow focus - all macros are slow
f. 1:2 ratio

Conclusion
Being an older lens, lots of people out there assume that the performance of this lens is sub-par. But looking at the results, you will see that good glass is good glass regardless of when it was built. If you don't need 1:1 and you are looking for a bargin in the 180mm range, this is definitely recommended - especially if you can get it for a good price on Ebay.

Strengths:
* image quality
* build quality
* works on new digital bodies

Weaknesses:
* weight

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2.
I hate to let this lens go. It is solid built(much more solid than any sigma current products). Nice optics. Beautiful lens made very sharp and contrasty pictures. But I have to let it go after I sold my last film EOS bodies. This lens doesn''t work on new EOS body, including my only left EOS D30 digital SLR. This lens was sent to sigma for upgrade, but it was sent back to me untouched. They can not upgrade this lens, that simple. Now I have to rely on my 70-200 f2.8 and 500D close up lens for similar macro performance. I have to say it is way worse than the sigma 180 f2.8. You can tell the difference even in the view finder.

Strengths:
Beautifull solid build quality. Excellent optical performance.

Weaknesses:
Imcompabilty. I hate sigma USA''s simple answer and their lack of responsbility on the imcompabilty issue. Tokina can upgrade their discontinued lens(such as Tokian 100 f2.8 macro), why not sigma?

Customer Service:
A kind of controversy. Sometime you got prompt service, sometime it could take more than one month. In this case, I hate their lackness of responsiblity. Who knows if I am going to buy any more sigma

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3.
The lens build quality and optics is definitely superior than the competition. Although this model is now discontinued it still is far more superior(and still costlier if you can find one used or brand new) than the Nikkor 180mm f2.8 and Sigma AF180mm f3.5 just released recently.

Strengths:
Super sharp and super fast apochromatic design professional telephoto lens, sharper than the Nikkor 180mm f2.8 I had before.

Weaknesses:
A bit heavy at 1350g and quite expensive at US $800.

prova qui

http://www.juzaphoto.com/it/articoli/recen...leconverter.htm

Il Sigma 180 f2.8 non è quello nuovo ( f3.5) che è un'ottica eccellente sotto tutti i punti di vista. E' quello che si vede qui:
http://www.dyxum.com/lenses/detail.asp?IDLens=188
E' grosso come un 80-200 f2.8 AFS e molto pesante, ha un curiosissimo collare per treppiedi posizionato molto in avanti. Diametro filtri 82mm, rapporto di riproduzione 1:2 a 64 cm . Af preistorico, no HSM ma alberino di trasmissione. Buona qualità di immagine.
Suo contemporaneo il piccolo, economico 180 Apo Macro f 5.6, dalla resa dignitosa e dalle dimensioni paragonabili al 200 f4 Ai.
Ciao,

Silvio