EF12 extension tube and 1.4 teleconverter

[scuba-s]

have a canon 40d am looking at a cheaper alternative to a 100mm i was told of a Canon 60mm, EF12 extension tube and 1.4 teleconvertor is there anyone who has them and if so what are there benefits and drawbacks and is there anyone who has this setup with ikelite housing?any help would be greatly appreciated
Steve

 

[bvanant]

Cheaper maybe, but what are you looking for?. Both the 100 and the 60 do 1:1 magnification. The main advantage of the 100 is a bit larger working distance. If you are trying to do greater than 1:1 either the extension tube or the 1.4 tele will help, but at the expense of some optical quality. Adding the extension tube to the 60 will not get you more working distance but rather less and you lose infinity focus. The 1.4 turns the 60 into an 84 mm lens with a magnification ratio of 1.4:1 but you lose a stop and some optical quality. Neither approach gets you to the advantages of the 100 which is a bit more working distance. What pictures do you want to take with the 100 that you can't get with the 60. In any case, the lens is about $600. If you are budget limited, the Sigma 105 is only $479 or so and is a nice lens.
Bill

 

[Maddog59]

Cheaper maybe, but what are you looking for?. Both the 100 and the 60 do 1:1 magnification. The main advantage of the 100 is a bit larger working distance. If you are trying to do greater than 1:1 either the extension tube or the 1.4 tele will help, but at the expense of some optical quality. Adding the extension tube to the 60 will not get you more working distance but rather less and you lose infinity focus. The 1.4 turns the 60 into an 84 mm lens with a magnification ratio of 1.4:1 but you lose a stop and some optical quality. Neither approach gets you to the advantages of the 100 which is a bit more working distance. What pictures do you want to take with the 100 that you can't get with the 60. In any case, the lens is about $600. If you are budget limited, the Sigma 105 is only $479 or so and is a nice lens.
Bill

I've been looking at the Sigma 105 for my D300s and from what I'm reading it looks like a pretty good lens.