Fotoartist Loc: Detroit, Michigan

You bring up a good point about Live View and auto focus. Focusing is more sensitive in that mode.

photoman43

The only way I knw how to get 1 : 1 and focus it properly is to use a macro lens that will go to 1 : 1. Then you focus that lens at its shortest focus point (not infinity) and you focus the lens and camera together using a focus rail. And I do this using manual focus only. Part of this is explained here:


https://www.facebook.com/watch/?v=10156688669311654

fetzler Loc: North West PA

When one focuses any lens the magnification of the in focus image changes. If one focuses on the head of a person with a 50mm lens (FF) at 15 ft and then focuses on the same head at 4 ft. The size of the persons head on the sensor is larger at 4ft than it is at 15 ft. Things are no different in macrophotography. When one focus a lens one is moving the lens from its infinity focus position to a new position further from the sensor. (some modern lenses do this in a complex way)

I have an Olympus 60mm auto focus macro lens. On the side of the lens is a dial that will automatically adjust the focus for 1:1. It is useful to get the lens in the close focusing position. After doing this I can use manual focus to keep the magnification at 1:1 or I can use auto focus to have an image that will have a magnification somewhat less than 1:1. I do both in practice.

I recently purchased a Laowa 25mm macro lens that can produce images from 2.5X to 5x. The focusing scale is marked in magnification units as in practice on this manual lens one sets the magnification and then moves the camera into position to achieve focus. I use a automatic focusing rail to move the camera into position as movements of only a few microns are important.

Focusing and magnification are always intertwined.

SuperflyTNT Loc: Manassas VA

Do you have a focus limiter switch? Or you’ll just be slightly inside the close focus distance and backing off slightly puts you there.

PHRubin Loc: Nashville TN USA

I suspect it is nothing more exotic than adjusting the distance using a macro rail as opposed to adjusting the camera after setting it for 1:1.
https://www.bhphotovideo.com/c/product/1574871-REG/nisi_nisi_nm_180_nisi_macro_focusing_rail.html?sts=pi&pim=Y

SuperflyTNT Loc: Manassas VA

I don’t see what’s hard to understand. He set it to 1:1, (I guess that means he manually adjusted the focus point all the way to the minimum). He set the camera up until the focus was pretty close then he used AF to fine tune it. Maybe it wasn’t exactly 1:1 when he was done, but close enough so you wouldn’t notice.

SuperflyTNT Loc: Manassas VA

Because Live View uses contrast detection rather than phase detection and it’s right off the image sensor.

therwol Loc: USA

I think it's a simple question with a simple answer. I've had to do this. If you pre-set the focus on a macro lens to 1:1 (all the way out on my lenses), you can't then refocus with autofocus and maintain that ratio. You don't want to change the focal point. You have to leave the focusing ring alone and move the camera/lens closer or farther away from your subject to focus and maintain that ratio. I once had my Nikon D810 with a 55mm f/2.8 AF mounted on an enlarger as a makeshift copy stand. I would focus the lens all the way out (1:1) and then I would move the enlarger platform up and down to focus and maintain that ratio. ( I was copying slides and negatives with the camera and wanted them to fill as much of the frame as possible.)

burkphoto Loc: High Point, NC

It has to have a buffer within which the focus bracket takes place. The actual 1:1 is on the camera side of the nearest image in the focus stack. The center point of actual focus is therefore a fraction less than 1:1, and all other images in the stack are as well.

jackm1943 Loc: Omaha, Nebraska

Actually it has three focus limit ranges, and I use them of course. It's just than when I try to focus it at absolute minimum distance to the mm, it starts hunting focus when I start the focus bracketing. If I back off just a mm or two, then re-autofocus, it works fine. It's really not a big issue, just something I have to be aware of.

amfoto1 Loc: San Jose, Calif. USA

Without seeing the video, I can't be sure...

But I think what you may be seeing is a "focus trap" or "focus trapping" technique.

Some cameras allow you to link the shutter release to focus detection. The camera will prevent the shutter from firing until it detects focus has been achieved.

What you probably saw in the video was the photographer switching to manual focus, setting the 1:1 magnification they wanted, then moving the camera closer or farther from the subject until focus is achieved. Only when focus is achieved does the camera release the shutter and take the shot.

Focus trap technique uses the same AF detection points as does autofocus. It may appear as if the photog is using autofocus, when they really aren't (you are correct, the shot would no longer be 1:1 if they allowed autofocus to change the point of focus).

My cameras don't happen to have that focus trap feature, but I use Focus Confirmation in a similar way when doing close-ups and macro shots. I simply watch until the focus is achieved and confirmed by the camera, before taking the shot.

Architect1776 Loc: In my mind

Never heard of what you are saying.
If I want 1:1 for some reason I set my lens to as close as it focuses (1:1) then move the camera and lens to get focus. Same as you do. I know of no other way either.
I have very seldom done that.
I compose and AF regardless of magnification ratio, it is just the lens goes to 1:1 is a plus.

wmurnahan Loc: Bloomington IN

Any focus changes the ratio. The only way I know to shoot 1:1 is with a focusing rail, the lens is at it's closest focus to get 1:1, to keep 1:1 you have to move the camera.

User ID

Your assumptions are well founded. Online videos are quite often useless.

Stick by what you already knee before seeing the video.

dsnoke Loc: North Georgia, USA

I think the 1:1 is the aspect ratio, not the magnification. Some Canon (I think) and Fuji cameras allow you to choose between 2 or 3 different aspect ratios before exposing an image. But just my opinion without knowing the specific youtube video in question.