Multiplyer with non-APO Lens

[jonathan_rush]

<p>I have a Sigma 70-300 f/4-5.6 that is not an APO model. I also have a SAKAR 2X multiplier that I've been dying to try out with the Sigma, once I can walk around outside again. As long as I make sure the last element in the Sigma won't touch anything in the SAKAR, I should be able to use it, right? In other words, the does the "no-multipliers on non-APO Sigmas" restriction only apply to Sigma multipliers?</p>

[User_502260]

<p>Even if you could use the Sakar 2X you would have a 140-600 f/8-11. Will your camera be able to focus such a slow combination? Could you even manually focus it?</p>

[miserere_mei]

<p>Where did you see this <em>"no-multipliers on non-APO Sigmas" restriction?</em></p>

<p>In any case, IQ will probably be pretty bad, and after you stop down the lens 2 stops (in the hope of improving IQ) you'll have a 600mm f/22 at the long end. Not the most useful lens... :-)</p>

[jonathan_rush]

<p>Oops! I thought I learned it here on this forum. But I can't find the post now.</p>