need help on 105/2 DC

[lsisaxon]

i know this sounds very technical, is it possible for you to test shooting at a ruler at F2.8 to verify if the focal point shifts when DC turn to F or R mode. i tested mind..realise it seems to shift ( read my earlier post). if not or too boring for you any shots at f2 w different DC setting will be great. thanks

The focus scale is only valid when the DC ring is at 0. It is normal for the focus to shift when you turn the DC ring, so focusing should be done after you turn the DC ring. IIRC, it's documented in the manual, so you should read it.

 

[surge]

The focus scale is only valid when the DC ring is at 0. It is normal for the focus to shift when you turn the DC ring, so focusing should be done after you turn the DC ring. IIRC, it's documented in the manual, so you should read it.

i read the manual and notice the focus will shift. so need to refocus. what i am saying is after you turn the ring, focus at 30cm mark say at f4R4, should the sharpness pt be the 30cm mark or is it moved to the front? cos i notice the sharpest pt is not the focused pt but slightly more from.

pardon me from being very technical. but i think it helps me in understanding how to use the lens better.

 

[lsisaxon]

i read the manual and notice the focus will shift. so need to refocus. what i am saying is after you turn the ring, focus at 30cm mark say at f4R4, should the sharpness pt be the 30cm mark or is it moved to the front? cos i notice the sharpest pt is not the focused pt but slightly more from.

pardon me from being very technical. but i think it helps me in understanding how to use the lens better.

Eh... I think that will vary on the CAM sensor used and if you MF, your eye that is.. ;p This is because once you shift the SA correction group, there will exist a secondary focus in addition to a primary focus, this secondary focus if not aligned with the primary focus will give you a halo like effect like for soft lenses. In the DC lens, the aperture used will determine if the DoF of the secondary focus is still within the limits of the primary focus, that is how the lens controls the defocus effect, so ddon't worry that much and just shoot. ;p

 

[surge]

Eh... I think that will vary on the CAM sensor used and if you MF, your eye that is.. ;p This is because once you shift the SA correction group, there will exist a secondary focus in addition to a primary focus, this secondary focus if not aligned with the primary focus will give you a halo like effect like for soft lenses. In the DC lens, the aperture used will determine if the DoF of the secondary focus is still within the limits of the primary focus, that is how the lens controls the defocus effect, so ddon't worry that much and just shoot. ;p

thanks! looking forward to this weekend to shoot w this lens. used it today to shoot some costume parade done by children. quite a miss and hit. 70-200 i am like 90% sure the shots will turn out sharp. this lens...more miss than hit. usually even though new lens, i don have such problems. guess i am still learning how to use it. thanks so much!

 

[agape01]

I think if you were to read the manual, you will know how to use this lens effectively.

my 2 cents.

 

[jeanie]

surge,
i'm so sorry.dont think i'll be able to shoot this weekend.

my monitor/graphics card is giving me problems.i got to get it sorted 1st.

apologies:embrass:

 

[surge]

surge,
i'm so sorry.dont think i'll be able to shoot this weekend.

my monitor/graphics card is giving me problems.i got to get it sorted 1st.

apologies:embrass:

its ok...am in no rush...i also didnt shoot....haha....am taking time to learn the new lens. i am pretty sure that my copy is good without any focusing issue after some testing...just need to learn how to use the lens properly.

did use it to take some kids in costume parade and even at f2, photos are sharp. guess really its a portrait lens...not suitable for taking wall test charts!:bsmilie: