Manual Focus Tweak
Jun 27, 2017 10:04:06 #
If I zoom in on my subject manually ro tweak my focus, will that focus hold when I zoom back out to compose the shot?
Jun 27, 2017 10:05:23 #
Not necessarily.
--Bob
--Bob
Patw28 wrote:
If I zoom in on my subject manually ro tweak my focus, will that focus hold when I zoom back out to compose the shot?
Jun 27, 2017 10:12:58 #
RWR
Loc: La Mesa, CA
Patw28 wrote:
If I zoom in on my subject manually ro tweak my focus, will that focus hold when I zoom back out to compose the shot?
If your lens is worth owning, focus will not change when you zoom in or out.
Jun 27, 2017 10:36:26 #
gvarner
Loc: Central Oregon Coast
If your camera is capable, it's common to zoom in on the LCD to fine tune the focus. Focus matrix patterns look at different things depending on what's in the field of view. My understanding is that they prioritize on the closest subject, assuming that's what you're capturing. This would hold for telephoto as well as wider focal lengths. So what's in focus might change as you change the focal length, depending on your focus matrix choices of course. Back button focusing might help too, again if you can set your camera up for that. Hold the button to get focus at any focal length. Release the button and focus doesn't change if you zoom or change the composition. Then take the shot. But there still may be lens issues that would result in a different focus point depending on focal length.
Jun 27, 2017 10:37:53 #
Jun 27, 2017 10:43:50 #
It depends... If you are not using the central focus point & keeping the same central point when backing off, then yes, it can change as using one other than the central one will change the scene dynamics.. Plus it also depends on whether it's a true zoom or a varifocal type. Try it out, that way you will know for sure.
Jun 27, 2017 11:48:07 #
Patw28 wrote:
If I zoom in on my subject manually ro tweak my focus, will that focus hold when I zoom back out to compose the shot?
It sounds like a good experiment for an afternoon when you have some free time.
Jun 27, 2017 13:54:14 #
Patw28 wrote:
If I zoom in on my subject manually ro tweak my focus, will that focus hold when I zoom back out to compose the shot?
Only if you shoot with a par focal lens, which most of todays lenses are not!
Jun 27, 2017 13:55:40 #
Patw28 wrote:
If I zoom in on my subject manually ro tweak my focus, will that focus hold when I zoom back out to compose the shot?
Most lenses are not parfocal, which is what you are asking, so the answer is probably not. It is not a measure of quality, but a design decision to not allow the physical size of the lens to change when you zoom. I've got the Nikon Holy Trinity, and 4 other zooms - none of which will reliably hold focus throughout it's zoom range.
This may explain things a little better:
https://www.lensrentals.com/blog/2016/03/mythbusting-parfocal-photo-zooms/
Even the $20K cine lenses from Zeiss say they are "mostly" or "almost" parfocal, none that I have seen actually say they are perfectly parfocal.
Jun 27, 2017 14:08:47 #
speters wrote:
Only if you shoot with a par focal lens, which most of todays lenses are not!
That's what I've found, but I didn't know if it was me or the lens. It's nice being able to blame the equipment.
Jun 28, 2017 06:18:08 #
Patw28 wrote:
If I zoom in on my subject manually ro tweak my focus, will that focus hold when I zoom back out to compose the shot?
I wish I had posted a more intelligent question!
I 'always' shoot BBF, spot metering, continuous focus, which is claimed to lock the focus when you release the button.
Now what should I believe? (I could write a book on "Gullible's Travels".)
Jun 28, 2017 10:25:54 #
wingclui44
Loc: CT USA
Patw28 wrote:
I wish I had posted a more intelligent question!
I 'always' shoot BBF, spot metering, continuous focus, which is claimed to lock the focus when you release the button.
Now what should I believe? (I could write a book on "Gullible's Travels".)
I 'always' shoot BBF, spot metering, continuous focus, which is claimed to lock the focus when you release the button.
Now what should I believe? (I could write a book on "Gullible's Travels".)
It doesn't matter if your zoom lens is par-focus lens or not, any time when you 'lock' the focus and then move your camera to recompose, the focus will change even a slight movement of your camera, unless "your camera is on the tripod". AFc/AFs-BBF focus only lock in the first focus attempt after the button is released/pressed, but can not lock the position of your camera. That's why I always do one more step after recompose, I will re focus again by moving the focus point to the object I need to focus.
Jun 28, 2017 10:44:42 #
Patw28 wrote:
If I zoom in on my subject manually or tweak my focus, will that focus hold when I zoom back out to compose the shot?
Most likely not, unless it is a parfocal lens, which is generally required for good quality video lenses, and also why they are typically so expensive. Difference in cost is around an order of magnitude - meaning ten times the cost for otherwise similar specifications.
If using BBF, then the focus may hold, but may not be accurate focus at different zoom levels.
Jun 28, 2017 11:40:34 #
"If your lens is worth owning, focus will not change when you zoom in or out."
Wow, and here I always thought the Nikon 70-200 L was worth owning. I guess I'll dump it.
Wow, and here I always thought the Nikon 70-200 L was worth owning. I guess I'll dump it.
Jun 28, 2017 11:45:44 #
joel.photography wrote:
"If your lens is worth owning, focus will not change when you zoom in or out."
Wow, and here I always thought the Nikon 70-200 L was worth owning. I guess I'll dump it.
Wow, and here I always thought the Nikon 70-200 L was worth owning. I guess I'll dump it.
A Nikon "L" lens?
New to me.
If you want to reply, then register here. Registration is free and your account is created instantly, so you can post right away.