Lens depth of field scales (Page 6): But upon what do they base the camera's decisions? What size print? Would they let you tell the camera to base the decision on a 6x4 inch size or a...

burkphoto Loc: High Point, NC

Mikeg50 wrote:

In my mirrorless viewfinder, there is a distance scale. Why cannot Canon have a triangle above the minimum focus distance, another above the maximum focus distance , and a third (of a different color) of the hyper focal distance. As you zoom, they would change. As you change f stop, they would change. Easy for a computer. Maybe if we all demanded this, it would be implemented. Every landscape photographer would be ready to purchase a new camera.

But upon what do they base the camera's decisions? What size print? Would they let you tell the camera to base the decision on a 6x4 inch size or a 60 inch by 40 inch size? Depth of field calculations should consider print size, because what's acceptable as "sharp" in small prints does not hold up as the image is enlarged.

Most of the calculators and scales developed over the years are based on 8x10 inch prints. They hold up well for larger prints, but only when viewing them at the diagonal of the print size or even farther away.

But for, say, a group photo of 425 people, we view prints up close, to see individual faces. THAT is where the depth of field scales fall apart, and you have to base aperture choice on print size as well as other factors.

NCMtnMan Loc: N. Fork New River, Ashe Co., NC

Check out this link. Maybe this will help you.

https://darrellyoung.com/blog/important-depth-of-field-preview-information-for-nikon-z-cameras

cjc2 Loc: Hellertown PA

burkphoto wrote:

But upon what do they base the camera's decisions?... (show quote)

A good point Bill!

Mikeg50 Loc: SE Missouri

You base it on the same parameters used when they put the scale on every lens. It is up to the photographer to make the final decision based in the parameters you mentioned. Nothing is precise but it would be an extremely useful aid. It could be turned off, just as the focus scale can be if you didn’t like it.

roger

Prime lenses are easier to show the depth of field scale as the focal length doesn't change.
It can be done on zooms, but is much, much more complicated.
Also, remember that DOF really should be depth of focus, not depth of field. There is really and truly only one point where a lens in in focus. Using a higher f-stop will make it "appear" sharper before and after that focus-point, but other point before and after are not really "in focus"!

burkphoto Loc: High Point, NC

roger wrote:

Prime lenses are easier to show the depth of field scale as the focal length doesn't change.
It can be done on zooms, but is much, much more complicated.
Also, remember that DOF really should be depth of focus, not depth of field. There is really and truly only one point where a lens in in focus. Using a higher f-stop will make it "appear" sharper before and after that focus-point, but other point before and after are not really "in focus"!

That's exactly what I was getting at when mentioning print size, above. The larger the print, the more critical it is to consider focus point and depth of focus. There are "rules of thumb," but they don't hold up at extremes of cropping or enlargement.

petrochemist Loc: UK

roger wrote:

Prime lenses are easier to show the depth of field scale as the focal length doesn't change.
It can be done on zooms, but is much, much more complicated.
Also, remember that DOF really should be depth of focus, not depth of field. There is really and truly only one point where a lens in in focus. Using a higher f-stop will make it "appear" sharper before and after that focus-point, but other point before and after are not really "in focus"!

Depth of focus is a term that already exists for a slightly different variable, it's like Depth of field but on the other side of the lens - how precise the film positioning needs to be... I've never had a need to use it, but it might be essential in camera manufacture...

frankraney Loc: Clovis, Ca.

Longshadow wrote:

My old SLR zoom had a logarithmic scale on the lens for DOF that "fanned out" for shorter focal lengths, different sections of the scale were visible depending on the focal length selected. It is not impossible....... Just an added cost process.

frankraney Loc: Clovis, Ca.

kernel bleep wrote:

Thanks, all. I didn't know DOF apps existed. I don't understand how they'd work but I'll look into the Android version. Might do the trick...

If you need help with the hyperfocal pro, Android version PM me. It's super easy and it's good. It's all done with calculations with aperture lens focal length and so on.

Mikeg50 Loc: SE Missouri

I don’t understand the resistance to this idea. You guys are throwing up “straw men”. There is a computer in the camera and software in the lens. It could be implemented very easily and more accurately than ever. I believe there was a photo posted earlier in this very thread of expanding depth of field lines on a zoom lens. A triangle over the closest focused distance and another over the maximum focused distance is EXACTLY a depth of field indication. In a computerized camera system it would be more accurate than has ever been able to be implemented. And it all would be much more accurate and convenient than using a smartphone app.

Mikeg50 Loc: SE Missouri

Here is how easy it is: buy the code from the people that have already developed it for the phone app (if you don’t wish to develop it in-house). Then, hire a high school freshman to develop the code that connects the already existing process of the lens telling the camera what f-stop, focal length, and distance focused is already set. Bingo. You are now ahead of every other camera manufacturer.

kymarto Loc: Portland OR and Milan Italy

kernel bleep wrote:

The only mirrorless camera I own is my Z50 so I do... (show quote)

Depth of field scales were, in the day, anyway only a guide, indicating what was considered acceptable focus. It is always that there is a point of sharpest focus, which gets progressively more unfocused before and behind.

With mirrorless, having focus magnification allows you to see exactly what is in acceptable focus for you at a given aperture, much better than some approximate scale on a lens barrel.

Canisdirus

Mikeg50 wrote:

I don’t understand the resistance to this idea. Y... (show quote)

Resistance from the manufacturers?

Simple...they gave us focus peaking...which gives real time DOF indicators right in the EVF.

I suspect the ones complaining/wishing are using older gear.

Why would the manufacturers put old tech on their new lenses...lenses not made for anything other than mirrorless bodies?
Mirrorless can use old DSLR lenses
DSLR bodies can't use the newer mirrorless lenses

Folks with newer gear...don't give a whit about DOF scales printed on their lenses...unneeded.
Manufacturers know this.

Jorgy

Longshadow wrote:

DOF scale removal was a cost cutter???

I used them a lot, when they existed.

These are really straightforward for fixed focal length lenses, but not so for zooms, especially with the extreme zoom ranges available now for digital photography.

kymarto Loc: Portland OR and Milan Italy

Canisdirus wrote:

Resistance from the manufacturers? br br Simple..... (show quote)

Modern lenses focus electronically with no hard stop for infinity. It would literally be impossible to put a DOF scale on a lens whose focus ring turns freely. You could put a scale on the barrel, but there could be no mark on the lens' focus ring to line up with it.