How Does A Camera Focus On Objects At Different Distances
Focusing 2 people at different distances
Hello,
I have a 600D and accept posted the following question in the rebel forum, but would like the stance of users of 5DII/5DIII/6D who have likewise used rebels, if they can tell me if these college cameras correspond a substantial comeback over the rebels for what I a asking:
I am taking photos at a wedding from the side. Being from the side information technology means that bride and groom are at differente distances. If I focus on the groom, the bride is out of focus. If I focus on the bride, the groom is out of focus.
How tin can I focus so that both are in focus ? I thougth that A-DEP way was for that, simply I don't go consequent results.
Of form I can focus on ane of them and set aperture to half dozen-7, simply and so the groundwork is dark because information technology does not collect light from backgroumd . If I increment ISO so I get too much dissonance.
Ideally in that location should be some way to tell the camera that I want both helpmate and groom to exist in focus and then the camera would automatically focus at a middle signal and so discontinuity would non demand to be reduced (f number increased) so drastically. I mean: if I could brand the photographic camera to focus at a middle point the aperture could be wider (and still keep both in focus) than if the camera focuses on one of the two.
I suppose this problem is faced past whatsoever photographer who has to have wedding photos from the side, if non one has to move position to be only in front of the couple, which would ruin the anniversary.
Thanks for your assistance
Jose Maria
24Peter • Veteran Member • Posts: four,758
Re: Focusing 2 people at different distances
Hullo Jose - unfortunately, there'due south no way to overcome the physics of light. For a given aperture, focal length and imaging size, you lot have a certain surface area of the image that will be in adequate focus. Our cameras - whether Rebels or otherwise - practise their best to machine focus only they tin can't read our minds. We need to pick a indicate of focus and then the camera will practise the balance. And then yous need to exercise your skill and discover a suitable mid-way point, then either manually focus or employ AF. A-DEP doesn't have anything to do with this.
The adept news is, at normal viewing distances for about print sizes, a minor departure in focus between two people standing next to each other won't be noticeable. It'southward just when nosotros view our images at 100% on a computer screen that our sense of dread sets in
OP josemaria2 • Regular Member • Posts: 341
Re: Focusing 2 people at different distances
merely my question is:
If at that place whatever fashion to brand the photographic camera focus at the eye betoken of the ii people ? Or the focus plane has to be on ane of them, non in the centre ?
In other words, my just pick is focusing at the starting time or end of the range, but not in the middle ?
I thought to focus in the middle of the 2 people I had to employ the A-DEP manner, and provided both people were defenseless by the focusing points it would set focusing plane at mid distance and so be able to keep both in focus with minimal loss of aperture.
Thanks to everybody for your assist
Regards
Jose Maria
Timbukto • Veteran Fellow member • Posts: 4,988
With today's current offerings, no
josemaria2 wrote:
but my question is:
If at that place any fashion to make the photographic camera focus at the middle point of the ii people ? Or the focus plane has to exist on one of them, not in the middle ?
In other words, my but choice is focusing at the get-go or end of the range, simply non in the middle ?
I idea to focus in the middle of the 2 people I had to use the A-DEP way, and provided both people were caught by the focusing points information technology would set focusing plane at mid distance and then be able to keep both in focus with minimal loss of aperture.
Thank you to everybody for your help
Regards
Jose Maria
Y'all would offset demand a mirrorless photographic camera that performs CDAF or PDAF on sensor too equally built in focus peaking and a lens with FTM. You would preferably want it to be EVF as well. Sony also has SLT, but keep in heed this arguably *hurts* your state of affairs to some degree since as you say stopping downward the lens gives you more DOF, and substantially makes information technology more than of a depression lite state of affairs which Sony SLT gives you lot a disadvantage in already eating up some calorie-free with the pellicle mirror.
So yous would want mirrorless, notwithstanding you volition exist at a disadvantage in low-light focusing potentially besides as just any other shot where you would not demand to shoot a group shot.
Withal I would agree that if some camera companies were smart they would market loftier-terminate mirrorless with the accented best FTM lenses in haptics, best focus peaking implementation, and you'd become a fun system to shoot that would excel in fine-tuning focus. So a camera with EVF, mirrorless, fast focus peaking, depression EVF lag, excellent FTM (often mirrorless lenses have fly-by-wire focusing with poorer haptics).
Sony NEX is the only system that comes close to achieving all of this with the use of focus peaking and legacy manual lenses! But it is *but* for MF...it volition not exercise it 'automatically' all for you. And so in a sense you could also *attempt* to do the same with an OVF photographic camera, MF, and FTM lenses where you focus for one...nudge the focus to exist inbetween, and stop down a fleck. So really yes you can dream for a camera that already does it for yous....or y'all can but effort to employ FTM on the camera you already accept. Also larger sensor cameras gives you lot far less benefit here in these type of shots where yous desire higher DOF.
Canon EOS M Canon EF 200mm f/ii.8L Two USM Canon EF-M 22mm f/2 STM
Re: With today's electric current offerings, no
Wouldn't any camera set to manually focus do this? Just manually focus mid-way between the bride and the groom, and set an aperture of around f/8.
Sony NEX is the only arrangement that comes close to achieving all of this with the use of focus peaking and legacy manual lenses! But information technology is *just* for MF...information technology volition non practise it 'automatically' all for y'all. So in a sense y'all could as well *try* to do the same with an OVF camera, MF, and FTM lenses where you focus for ane...nudge the focus to be inbetween, and stop down a chip. So really yes y'all tin can dream for a camera that already does it for y'all....or you can just endeavour to employ FTM on the photographic camera you already take. Likewise larger sensor cameras gives you far less do good here in these type of shots where you desire higher DOF.
(unknown fellow member) • Senior Member • Posts: 2,261
Think I'll grab a BLT for lunch. ;)
No text.
bhollis • Veteran Member • Posts: 3,912
Re: Focusing ii people at unlike distances
josemaria2 wrote:
but my question is:
If there any way to make the camera focus at the middle point of the 2 people ? Or the focus plane has to be on one of them, not in the middle ?
In other words, my only pick is focusing at the beginning or stop of the range, merely not in the middle ?
I thought to focus in the centre of the ii people I had to apply the A-DEP mode, and provided both people were defenseless by the focusing points it would set focusing plane at mid distance and so be able to keep both in focus with minimal loss of discontinuity.
Sorry, don't know anything about A-DEP fashion on a rebel, nor practise I know much near rebels in full general But I'one thousand assuming that there's a way for you lot to focus using a spot in the viewfinder where y'all put this spot on the subject you desire to focus on and then lock focus. If so, and so put this spot on some object between your 2 subjects. If they're holding hands, focus on the hands. Or if they're standing immediately next to each other, focus on the arm of the nearest subject--i.e., the arm that is farthest away from you.
And of course yous'll need to select an appropriate aperture to give you plenty depth of field to cover both subjects.
Sony RX1R Canon EOS 5D Marker IV Nikon Z7 Catechism EF lxx-200mm F4L IS USM Canon EF 24-70mm F2.8L Ii USM +iv more
OP josemaria2 • Regular Member • Posts: 341
Re: Focusing 2 people at unlike distances
If so, so put this spot on some object between your two subjects. If they're holding easily, focus on the hands. Or if they're standing immediately side by side to each other, focus on the arm of the nearest subject--i.e., the arm that is uttermost away from you.
My question is almost the situation where at that place is zero in the middle to bespeak the center focus. I just idea these higher cameras had some way of computing automatically the middle signal of the two people, only I see I was mistaken. However, in my humble opinion, it should not be that difficult for photographic camera manufacturers.
Thanks for your help
missbrand • Regular Member • Posts: 178
Depth of Field
Hi
Y'all need to calculate DOF. In order to do this, y'all need to input distance to object, lens focal length, aperture and size of sensor, variate aperture, distance and/or lens focal length until DOF is large enough to cover both persons. Take ISO and shutter speed into consideration:-)
Computer:
http://www.dofmaster.com/dofjs.html
Regards
Michael
Canon EOS-1Ds Mark II Catechism EF 24-70mm f/2.8L USM Canon EF seventy-200mm f/2.8L IS USM +1 more
Timbukto • Veteran Fellow member • Posts: 4,988
Re: With today'due south current offerings, no
phototeacher wrote:
Wouldn't any camera set to manually focus do this? But manually focus mid-style between the bride and the groom, and prepare an aperture of around f/8.
Yes, only the OP wanted some 'automated' style of doing it. Likewise he was thinking A-DEP style (auto DOF mode that existed a short time on Rebels) would do a better task. Nevertheless with thin focus points and AF systems that are relatively still 'impaired', no it cannot exercise this.
And then once more the *nigh* automatic or camera facilitated way is an EVF + focus peaking + MF. Although yes using OVF you can pretty much get shut enough with DOF preview.
IMO the A-DEP feature which doesn't work well with thin PDAF *can* exist implemented in modernistic mirrorless camera'due south using a combination of CDAF, face tracking, etc. Information technology only hasn't notwithstanding. I.due east. a photographic camera where you just point and shoot and it does *everything* for you including 'optimum' DOF.
Besides the OP doesn't realize that as yous motility *upward* in higher-finish cameras they actually tend to do *less* automatically for y'all!
Catechism EOS M Canon EF 200mm f/2.8L II USM Catechism EF-M 22mm f/two STM
(unknown fellow member) • Veteran Member • Posts: 5,590
Re: Focusing 2 people at different distances
josemaria2 wrote:
If and so, then put this spot on some object betwixt your two subjects. If they're property hands, focus on the hands. Or if they're standing immediately adjacent to each other, focus on the arm of the nearest subject--i.e., the arm that is farthest away from you lot.
My question is about the situation where at that place is nothing in the eye to point the eye focus. I simply thought these higher cameras had some way of calculating automatically the centre betoken of the 2 people, only I see I was mistaken. Even so, in my humble stance, it should not be that difficult for camera manufacturers.
Cheers for your assistance
The a-dep mode should do what you desire but I wonder if you are using as Canon intended, i.e. you take two focus readings - one on the about point and ane on the far point and so when you take the shot the focus bespeak and the required discontinuity will exist calculated past the camera. But in case have a read of this - http://www.digital-photograph-secrets.com/tip/1557/what-is-a-dep-on-a-canon-camera-and-how-do-i-utilize-it/
Timbukto • Veteran Member • Posts: iv,988
Re: Focusing two people at different distances
meland wrote:
josemaria2 wrote:
If and so, then put this spot on some object between your two subjects. If they're holding easily, focus on the easily. Or if they're standing immediately side by side to each other, focus on the arm of the nearest subject--i.e., the arm that is farthest away from yous.
My question is about the state of affairs where there is nothing in the heart to point the center focus. I just idea these higher cameras had some way of computing automatically the middle betoken of the 2 people, but I see I was mistaken. However, in my humble opinion, it should not exist that difficult for photographic camera manufacturers.
Thanks for your aid
The a-dep mode should do what you desire but I wonder if you are using as Canon intended, i.due east. you take ii focus readings - one on the about point and ane on the far indicate and then when you have the shot the focus betoken and the required aperture will be calculated by the photographic camera. Just in case have a read of this - http://world wide web.digital-photograph-secrets.com/tip/1557/what-is-a-dep-on-a-canon-camera-and-how-do-i-employ-it/
I had the Rebel with A-DEP and that article is inaccurate on how it works. You practice non pick closest and farthest point, etc. I think that A-DEP is how some one-time film camera implemented it not how the Insubordinate one did.
Keep in heed this mode had since been removed from the t2i/t3i, etc in later models.
Canon EOS M Canon EF 200mm f/two.8L II USM Canon EF-Chiliad 22mm f/2 STM
(unknown member) • Veteran Fellow member • Posts: 5,590
Re: Focusing 2 people at dissimilar distances
Timbukto wrote:
meland wrote:
The a-dep manner should practise what yous want simply I wonder if yous are using every bit Canon intended, i.e. you take two focus readings - one on the near bespeak and one on the far betoken and so when you lot take the shot the focus point and the required aperture will be calculated by the camera. Just in example take a read of this - http://www.digital-photograph-secrets.com/tip/1557/what-is-a-dep-on-a-canon-camera-and-how-practise-i-utilize-it/
I had the Insubordinate with A-DEP and that commodity is inaccurate on how it works. You do non pick closest and farthest signal, etc. I think that A-DEP is how some old motion-picture show photographic camera implemented information technology non how the Insubordinate ane did.
Keep in mind this mode had since been removed from the t2i/t3i, etc in afterwards models.
Y'all are indeed correct - I see Canon take inverse the way A-Dep works on cameras such as the 600D compared with before models.
Co-ordinate to the instruction manual, which I've just had a quick look at, if your 2 subjects (near and far) are covered by the camera'south AF sensors and there is no blinking of the aperture display (which indicates that the necessary discontinuity can not be set) then the photographic camera should exist able to fix the necessary focus point, discontinuity and exposure automatically.
Does your 600D non do that? Could it be that your subjects are also far autonomously to be covered past the AF sensors?
Timbukto • Veteran Member • Posts: 4,988
Re: Focusing 2 people at dissimilar distances
meland wrote:
Timbukto wrote:
meland wrote:
The a-dep mode should do what you want but I wonder if yous are using as Canon intended, i.e. you accept two focus readings - ane on the near point and one on the far point and so when y'all take the shot the focus point and the required discontinuity will exist calculated by the photographic camera. Just in case have a read of this - http://world wide web.digital-photo-secrets.com/tip/1557/what-is-a-dep-on-a-catechism-camera-and-how-practise-i-utilize-it/
I had the Rebel with A-DEP and that article is inaccurate on how information technology works. You lot do not pick closest and farthest signal, etc. I call up that A-DEP is how some old film photographic camera implemented information technology non how the Insubordinate one did.
Keep in mind this mode had since been removed from the t2i/t3i, etc in later models.
You are indeed correct - I see Canon have changed the manner A-Dep works on cameras such as the 600D compared with earlier models.
According to the educational activity manual, which I've only had a quick await at, if your two subjects (near and far) are covered by the photographic camera'south AF sensors and there is no blinking of the aperture brandish (which indicates that the necessary aperture can not be set) then the camera should exist able to set the necessary focus bespeak, aperture and exposure automatically.
Does your 600D not do that? Could it be that your subjects are too far apart to be covered by the AF sensors?
Of course information technology did not do that. For all of that to really happen you would accept to believe that Canon with its PDAF sensors fifty-fifty *knows* what your subject area is! If information technology cannot fifty-fifty really do face detection with a *single* person, what is the gamble it can detect two faces and interpolate the distance and summate DOF for you?
I really have no idea how information technology *really* worked in terms of engineering science but based on results its most likely more marketing than technology. If Magic Lantern can't focus bracket and perform this adding for y'all, I actually doubt Canon has annihilation up their sleeves for a *existent* working A-DEP.
Basically the style it probably works is that the camera 'queries' the phase departure at each of the bachelor focal points, does some silly simplified averaging to calculate DOF...and will probably requite you actress stopped down apertures for a margin of rubber....
Call back of it as all-surface area auto-AF + a lot of stopping down and that is a good idea of how A-DEP worked...in a word pretty useless.
Catechism EOS Thou Canon EF 200mm f/ii.8L Two USM Canon EF-M 22mm f/2 STM
(unknown fellow member) • Veteran Member • Posts: 5,590
Re: Focusing 2 people at different distances
Timbukto wrote:
meland wrote:
Timbukto wrote:
meland wrote:
The a-dep fashion should do what you desire simply I wonder if you are using equally Canon intended, i.e. you take two focus readings - 1 on the near point and i on the far indicate and and then when you accept the shot the focus betoken and the required aperture will be calculated by the camera. Just in case have a read of this - http://www.digital-photo-secrets.com/tip/1557/what-is-a-dep-on-a-canon-camera-and-how-exercise-i-use-information technology/
I had the Rebel with A-DEP and that article is inaccurate on how it works. Yous do not pick closest and farthest betoken, etc. I think that A-DEP is how some quondam film camera implemented information technology not how the Rebel one did.
Go along in mind this mode had since been removed from the t2i/t3i, etc in after models.
You lot are indeed right - I see Canon accept changed the way A-Dep works on cameras such as the 600D compared with earlier models.
Co-ordinate to the instruction manual, which I've just had a quick await at, if your ii subjects (near and far) are covered past the camera's AF sensors and there is no blinking of the aperture display (which indicates that the necessary aperture can non be gear up) then the camera should be able to set the necessary focus point, aperture and exposure automatically.
Does your 600D not do that? Could it be that your subjects are besides far apart to be covered by the AF sensors?
Of class information technology did not practice that. For all of that to really happen you would have to believe that Canon with its PDAF sensors even *knows* what your subject area is! If information technology cannot even really do face detection with a *single* person, what is the chance information technology tin detect two faces and interpolate the altitude and summate DOF for you?
I really accept no idea how information technology *really* worked in terms of engineering but based on results its most likely more marketing than engineering. If Magic Lantern tin't focus bracket and perform this calculation for y'all, I actually doubtfulness Canon has annihilation up their sleeves for a *real* working A-DEP.
Basically the way it probably works is that the camera 'queries' the phase deviation at each of the available focal points, does some featherbrained simplified averaging to calculate DOF...and will probably requite you actress stopped down apertures for a margin of prophylactic....
Think of information technology as all-area auto-AF + a lot of stopping down and that is a practiced thought of how A-DEP worked...in a give-and-take pretty useless.
It's nothing to practise with 'face detection' if that's what yous are suggesting. All it does is have altitude readings at the left and right sensor points, calculate the aperture necessary to give the necessary depth of field to accept both those points in focus and gear up the hyperfocal altitude between the two. Of class whether this tin work reliably depends on the user being able to position the sensor points on his key subjects. Chances are he may non be able to in many cases which is where the system may fail.
The original A-Dep mode (with two separate focus readings from the heart focus point) did work quite well - although it was probably too fiddly for novices and experienced users didn't really need information technology anyway.
As an aside the Contax organisation that showed a distance calibration in the viewfinder and an illuminated bar superimposed on the scale that expanded / contracted to indicate depth of field had some promise. Unfortunately Contax are no longer with united states of america and information technology's non of much help hither in any instance.
Timbukto • Veteran Member • Posts: 4,988
Re: Focusing 2 people at different distances
meland wrote:
Timbukto wrote:
meland wrote:
Timbukto wrote:
meland wrote:
The a-dep mode should do what you lot want but I wonder if you are using as Canon intended, i.e. you have 2 focus readings - 1 on the near point and 1 on the far point and then when you take the shot the focus point and the required aperture will exist calculated by the camera. Just in case have a read of this - http://www.digital-photo-secrets.com/tip/1557/what-is-a-dep-on-a-canon-camera-and-how-do-i-employ-it/
I had the Rebel with A-DEP and that article is inaccurate on how information technology works. You do not pick closest and farthest signal, etc. I call back that A-DEP is how some old film photographic camera implemented it not how the Rebel one did.
Go along in mind this style had since been removed from the t2i/t3i, etc in afterward models.
Y'all are indeed correct - I see Canon take changed the way A-Dep works on cameras such as the 600D compared with earlier models.
According to the teaching manual, which I've just had a quick wait at, if your two subjects (near and far) are covered past the photographic camera's AF sensors and at that place is no blinking of the aperture display (which indicates that the necessary aperture can not be prepare) then the camera should be able to set the necessary focus bespeak, aperture and exposure automatically.
Does your 600D not do that? Could it exist that your subjects are also far autonomously to be covered by the AF sensors?
Of course it did non do that. For all of that to really happen you would have to believe that Canon with its PDAF sensors even *knows* what your subject field is! If it cannot even really do confront detection with a *single* person, what is the chance it can detect two faces and interpolate the distance and summate DOF for you?
I really take no thought how it *really* worked in terms of engineering but based on results its nearly likely more than marketing than engineering. If Magic Lantern can't focus subclass and perform this calculation for you, I really incertitude Canon has anything upward their sleeves for a *real* working A-DEP.
Basically the way it probably works is that the camera 'queries' the stage difference at each of the bachelor focal points, does some featherbrained simplified averaging to calculate DOF...and will probably give you actress stopped downwardly apertures for a margin of prophylactic....
Retrieve of information technology as all-area auto-AF + a lot of stopping down and that is a good idea of how A-DEP worked...in a word pretty useless.
It's zilch to do with 'face detection' if that's what you are suggesting. All information technology does is take altitude readings at the left and right sensor points, summate the aperture necessary to give the necessary depth of field to accept both those points in focus and ready the hyperfocal distance between the two. Of course whether this can work reliably depends on the user beingness able to position the sensor points on his central subjects. Chances are he may not be able to in many cases which is where the system may fail.
The original A-Dep mode (with two separate focus readings) did work quite well - although it was probably besides fiddly for novices and experienced users didn't really need it anyway.
As an aside the Contax system that showed a distance scale in the viewfinder and an illuminated bar superimposed on the scale that expanded / contracted to indicate depth of field had some promise. Unfortunately Contax are no longer with u.s.a. and it's not of much help here in any case.
That is my indicate...information technology tries to make up one's mind it based on the largest 'gap' between 2 PDAF sensors, nonetheless for someone who believes its all 'automobile-magic' they might believe that it somehow tries to understand your *bailiwick* based on the manual or marketing speak. No information technology does not...it has no existent potent understanding of your subject. Therefore whatever the PDAF point lands on is completely arbitrary as it usually is in all-area AF mode (i.due east. virtually of the automobile modes). For all nosotros know that PDAF betoken it uses for adding is looking at something through a large distance outside a window that volition get blown out anyways!
Even the sometime film-era way is too cumbersome...if it is a static scene that never changes, than you lot have all the time in the earth to get it correct anyways. If information technology is a fleeting moment of motility of multiple subjects, you need probably to be prepared first of all and perhaps use zone focus, etc. Nevertheless probably the *fastest* camera that can visualize 'zone-focusing' for you is an EVF camera that does focus peaking.
Canon EOS M Canon EF 200mm f/2.8L II USM Canon EF-K 22mm f/2 STM
qianp2k • Forum Pro • Posts: ten,350
Re: Focusing 2 people at different distances
TS-E lenses may be a solution. Canon has 17mm, 24mm, 45mm and 90mm TS-E lenses. With all-encompassing Tilt you tin achieve unbelievable deep DOF that regular lenses unable to deliver. They are manual focus lenses however, but you could pre-focus beginning.
http://www.dpreview.com/lensreviews/canon_24_3p5_tse_c10/5
Re: Focusing 2 people at different distances
I'm suspecting based on your question that you're looking for a solution on the less complicated cease of the scale. That would rule out TS-E lenses and such.
The simple answer to your question is no...there is no automatic method of getting that mid focal bespeak you want. It'southward pretty easy to obtain with some manual intervention though.
Equally mentioned above, you'll need to select a larger fstop f8 or above if possible. Select the nearest subject and lock focus with autofocus, switch on manual focus without turning the focus ring and so rotate the band to start to bring the dorsum discipline in focus -- no more than halfway in between. As long every bit y'all stay inside your DoF range, y'all'll take both in focus.
In practical use, the all-time matter to do is but to avoid the situation altogether if possible. I try to position myself with my subject area on an fifty-fifty plane as much as possible to fit within the focus range. Granted, that'southward not always possible or artistically preferred.
The other thing y'all can practice to assist is back abroad from your subjects. The farther away you are, the less pocket-size distance variations will thing. Go along in mind, however, that zooming in will decrease the DoF, and then you take to strike a residual.
Canon EOS 5D Mark Ii Canon EOS 40D Canon EOS-1D X Canon EOS 5D Mark Iii Canon EOS 70D +17 more
1
Only focus stack in software. I ran into this sometimes with formals at weddings. Recently, software has been able to assist here by snapping two pictures quickly with a slight manual focus adjustment between. Often, if you are quick enough, the blend is fairly easy. Another option is using a TS lens, but ane has to sentinel for possible baloney.
Dave Luttmann wrote:
Merely focus stack in software. I ran into this sometimes with formals at weddings. Recently, software has been able to aid here by snapping two pictures quickly with a slight manual focus adjustment between. Oft, if you are quick plenty, the blend is fairly easy. Another option is using a TS lens, but one has to watch for possible baloney.
He doesn't empathise the about rudimentary functions of a camera and lens, and y'all're suggesting prototype stacking and TS lenses. The best photographers in 2 forums take tried their all-time to help him and he even so doesn't believe a single ane of them. He's not looking for help. He'due south looking for a camera that will make him look similar a photographer.
Steve
Source: https://www.dpreview.com/forums/thread/3502949
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