[strangeboy]

Hello all...
+8 focus adjustment. Seems a bit much for a new and fairly modern lens. Is this weird? Has anyone else needed such an adjustment for your new lenses?

Most of my lenses are used K and M beauties, so I'm a bit outta water here. Thanx!

[Unregistered User 8]

Samyang 35mm f/1.4 Focus Adjustment

Hi strangeboy. As the lens is manual focus ( I think from the specs ), the AF ( auto focus ) adjustment feature does not apply.

[MJKoski]

How do you adjust AF for MF lens? Samyang 35mm has been full manual so far.

[strangeboy]

Yes. You can set the focus adjustment for manual lenses using the "AF Fine Adjustment: Apply All".

Check your manuals, folks.

[Unregistered User 8]

Check your manuals, folks.

" Apply All " means the same value is put on all AF lenses mounted on the camera, not all lenses. Manual focus lenses cannot be adjusted.

[strangeboy]

" Apply All " means the same value is put on all AF lenses mounted on the camera, not all lenses. Manual focus lenses cannot be adjusted.

Apply all is the only way to adjust manual lenses. I have done this for a couple mine: Porst 55mm f/1.2 which requires a -4, and the K 50mm f/1.4 at -2. There are a number of threads here that discuss this.

---------- Post added 09-16-16 at 08:50 PM ----------

Apply all is the only way to adjust manual lenses. I have done this for a couple mine: Porst 55mm f/1.2 which requires a -4, and the K 50mm f/1.4 at -2. There are a number of threads here that discuss this.

There is no chip in these lenses that the camera can read, which is why you must use Apply All.

---------- Post added 09-16-16 at 09:03 PM ----------

Here is one discussion: https://www.pentaxforums.com/forums/115-pentax-k-5/171047-focus-confirmation-manual-lenses.html

---------- Post added 09-16-16 at 09:12 PM ----------

Apply all is the only way to adjust manual lenses. I have done this for a couple mine: Porst 55mm f/1.2 which requires a -4, and the K 50mm f/1.4 at -2. There are a number of threads here that discuss this.

---------- Post added 09-16-16 at 08:50 PM ----------



There is no chip in these lenses that the camera can read, which is why you must use Apply All.

---------- Post added 09-16-16 at 09:03 PM ----------

Here is one discussion: https://www.pentaxforums.com/forums/115-pentax-k-5/171047-focus-confirmation-manual-lenses.html

Manual lenses (i.e. lenses that the camera doesn't recognize) will need to use the global adjustment (Apply All) rather than a lens-specific adjustment (Apply One).

Read more at: Fixing Front and Back Focus - The Remedy - In-Depth Articles

---------- Post added 09-16-16 at 09:14 PM ----------

Now... back to the OP.
Has anyone with reasonably new manual focus lenses ever had to make such large adjustments? Is this normal?
Thanks, again!

[UncleVanya]

Mount and lens tolerances are not perfect and with modern sensor resolutions it is easy to have a lens / camera mount combo that needs a large value. That same lens may be a 0 or a minus 7 or a plus 1 on another camera body.

[strangeboy]

How do you adjust AF for MF lens? Samyang 35mm has been full manual so far.

AF is something of a misnomer, since you can also compensate for manual focus lenses. You can make adjustments for Manual Focus lenses using the "Apply All" feature. This will move the focus either forward or backward. Unlike Autofocus lenses, the camera will not remember to which lens this adjustment should be applied, that is up to you. The thing I had to remember was to turn it off when attaching a different lens.
Fixing Front and Back Focus - The Remedy - In-Depth Articles

---------- Post added 09-16-16 at 09:26 PM ----------

Mount and lens tolerances are not perfect and with modern sensor resolutions it is easy to have a lens / camera mount combo that needs a large value. That same lens may be a 0 or a minus 7 or a plus 1 on another camera body.

Thanks... Just wondering what others have experienced.

[UncleVanya]

Thanks... Just wondering what others have experienced.

Gotcha. The only Samyang I have is the 8mm fisheye and honestly I don't even really try to focus it. I just use f/8 at hyper focal most of the time.

[Adam]

Hi strangeboy. As the lens is manual focus ( I think from the specs ), the AF ( auto focus ) adjustment feature does not apply.

This. AF confirmation has so much tolerance that applying fine adjustments is moot for MF lenses.

Use focus peaking or LV magnification instead

[strangeboy]

This. AF confirmation has so much tolerance that applying fine adjustments is moot for MF lenses.

Use focus peaking or LV magnification instead

Not my experience. I often shoot at f/1.2 and f/1.4. I also use a Katzeye Focusing screen. These adjustments make a difference for me and a number of other shooters.

[biz-engineer]

Can be, af tuning is taken into account for focus confirmation in the viewfinder; but it can be that there is a certain amount in random error from the focusing confirmation range itself. The +8 adjustment may not be the best value. I'd shot a multiple shots with each adjustment value and later on select the adjustment value that provide the best set of images. It is possible that +8 adjustment is required for your Samyang, but I wouldn't be worried so much. Canon adjustment range is wider, e.g +-20um range. You can have up to +10 or -10 adjustment on the Pentax camera, it does not mean the lens is defective, it's fine.

[strangeboy]

Can be, af tuning is taken into account for focus confirmation in the viewfinder; but it can be that there is a certain amount in random error from the focusing confirmation range itself. The +8 adjustment may not be the best value. I'd shot a multiple shots with each adjustment value and later on select the adjustment value that provide the best set of images. It is possible that +8 adjustment is required for your Samyang, but I wouldn't be worried so much. Canon adjustment range is wider, e.g +-20um range. You can have up to +10 or -10 adjustment on the Pentax camera, it does not mean the lens is defective, it's fine.

Thanx, biz. That's the info I was looking for. This lens is a departure for me since I shoot overwhelmingly with my beloved K lenses. I have a K 35mm f/3.5 arriving any day now, but I'd read such good stuff about the Samyang, that I bought it just to try it out. I'm not sure if it's a keeper yet.

So far it seems very useful wide open, f/1.4. I'll see how it stacks up to the legendary K 35 in a few days.

Thanks again.