I'm using D90 and AF-S mode for a while. I often rotate manual focus ring for precise adjustment after AF is done (the focus switch of lens or body is still on AF).

Will this damage the lens? It seems the focus ring of the Tamron 28-75mm/2.8 does not move as smoothly as it's on MF mode when I rotate it.

Please note that there's a very important difference between the focusing mode of the camera (AF-S, AF-C, AF-A, etc.) and the focusing design of the lens itself. The answer to your question depends on the lens:

1. On an AF lens, with a screwdriver-type focus, you should either use the AF or the MF, but never both. It will definitely damage the lens.

2. On an AF-S lens, which uses an ultrasonic signal to drive focus instead of a physical connection, the lens has focus designations of "M/A" and "A". On these lenses, you can do as you've suggested (focus with the camera and then fine-tune manually) with no problem whatsoever.

Nikon calls these AF-S lenses, Sigma calls them HSM, and I'm not sure what Tamron calls them. But check carefully, because it's the lens that determines whether or not what you're doing will damage it.

Tamron does not allow to do focus correction. Only do this with M/A-A AF-S lenses.

Guy

1. On an AF lens, with a screwdriver-type focus, you should either use the AF or the MF, but never both. It will definitely damage the lens.

Screwdriver-type AF BODIES will be the first to get damaged. I don't imagine it'll do wonders for the mechanical gearing in your lens either, but the body's focusing motor will eat it first. I learned this the hard way on my N70 back in the day

That resistance you are feeling when you try to MF your 28-75/2.8 is your D90's focusing motor crying in pain. Please stop! If the lens isn't a Nikon AFS "Silent Wave Motor" lens with an M/A - M switch, or if it isn't a Sigma HSM lens, DO NOT USE MANUAL FOCUS WITHOUT DISENGAGING YOUR BODY'S AF SCREW (clicking the lever by the lens mount to MF)!!!!!!!

Thank god I havent done it much. Thank you guys!

Rodolfo Paiz wrote:
Please note that there's a very important difference between the focusing mode of the camera (AF-S, AF-C, AF-A, etc.) and the focusing design of the lens itself. The answer to your question depends on the lens:

1. On an AF lens, with a screwdriver-type focus, you should either use the AF or the MF, but never both. It will definitely damage the lens.

2. On an AF-S lens, which uses an ultrasonic signal to drive focus instead of a physical connection, the lens has focus designations of "M/A" and "A". On these lenses, you can do as you've suggested (focus with the camera and then fine-tune manually) with no problem whatsoever.

Nikon calls these AF-S lenses, Sigma calls them HSM, and I'm not sure what Tamron calls them. But check carefully, because it's the lens that determines whether or not what you're doing will damage it.
Not all AF-S have the M/A capability. The 18-55 for example don't have it but then again, it's not really designed to focus manually.

Gustaf Lindber wrote:
Rodolfo Paiz wrote:
Please note that there's a very important difference between the focusing mode of the camera (AF-S, AF-C, AF-A, etc.) and the focusing design of the lens itself. The answer to your question depends on the lens:

1. On an AF lens, with a screwdriver-type focus, you should either use the AF or the MF, but never both. It will definitely damage the lens.

2. On an AF-S lens, which uses an ultrasonic signal to drive focus instead of a physical connection, the lens has focus designations of "M/A" and "A". On these lenses, you can do as you've suggested (focus with the camera and then fine-tune manually) with no problem whatsoever.

Nikon calls these AF-S lenses, Sigma calls them HSM, and I'm not sure what Tamron calls them. But check carefully, because it's the lens that determines whether or not what you're doing will damage it.
Not all AF-S have the M/A capability. The 18-55 for example don't have it but then again, it's not really designed to focus manually.
Yup, it just says A or M on the lens.