If you are currently reading this post, it is certainly because you are considering buying a 400mm lens for your Canon DSLR on a limited budget.

I wont go in details about the performances of this lens. If you believe only in measurements, I would suggest to read the test made by photozone.de. 

I use this lens on a EOS 5D mark II and to summarize my personal opinion about this lens, I can confirm the optical quality is fantastic and the mechanical quality is average.

The sigma 400mm f/5.6 APO HSM macro  was quite popular 10 years ago but unfortunately Sigma stopped the production early 2000. As many other old Sigma lenses, this lens is well known to have issues with the new Canon cameras (digital or late film cameras). Among the known problems, the aperture might be limited to f5.6 (still usable) or worst, your lens can be incompatible with your camera (error 99).

However, some of those lenses have been sent back to Sigma by their owner to be re-chipped, this operation making them compatible with the brand new EOS models. Sigma stopped this support in 2002 or 2003 as they ran out of microchips. Be aware before buying one of those lens!

Different models of this lens exist:

• Sigma 400mm/f5.6 APO
• Sigma 400mm/f5.6 APO HSM
• Sigma 400mm/f5.6 APO HSM Macro (the last version)

I bought my Sigma 400mm/f5.6 APO HSM Macro for ~US$600 on Trademe (kiwi avatar of ebay)  after the seller confirmed me that his lens has been re-chipped in 2001. However the seller never tried this lens on a modern DSLR so I was not certain it would work on my 5D mark II. I could not find any clue on internet neither about its compatibility with the EOS 5D mkII which would have helped me in my buy. At the end, I won the auction and….. good on me, IT WORKS PERFECTLY WELL!!! No error 99 and I works like a charm.

I hope those information might be useful to other people!

Many pictures made with this lens can be seen in my wildlife photo galleries Antarctica but here are view samples.