how to get sharp group picture

[cdjr4@cox.net]

I can't seem to get this right. I've tried everything, but can't seem to get everyone in sharp focus. I usually use center point, AV f4-11(I've tried them all) 30D 17-55 IS..... daytime, open shade outside shots iso 200-400. Any ideas? Usually a group of 5-10 people. Thanks in advance

[SkipD]

I can't seem to get this right. I've tried everything, but can't seem to get everyone in sharp focus. I usually use center point, AV f4-11(I've tried them all) 30D 17-55 IS..... daytime, open shade outside shots iso 200-400. Any ideas? Usually a group of 5-10 people. Thanks in advanceFirst of all - using your email address as your logon name in a forum is not a good idea. It will allow spammers to learn your email address and flood you with garbage emails. I would suggest contacting the moderators and changing your logon name to something that does not represent your email address or even the email mailbox that you use.

For the photo issue, if you can post a sample or two with exposure information and 100% crop sections of the photos (so we can see the fine detail), maybe we can give you some real advise. Otherwise, we'd be guessing.

[Tony-S]

Have you tried using fill flash on program or some such?

[PhotosGuy]

Why are the subjects at the outside edges of the photo so out of focus; F/4 is not enough. The "plane of focus" isn't a flat plane. It's a curve. and thought that the camera was set to A-DEP until I looked at the properties on the PC and it shows Manual. I ONLY shoot on "M" & never trust the cam to know what I'm thinking?
You could get rid of that hot spot in the middle of that pic by putting the flash a bit off to the side, or get a cheap slave & try this next time.
Simple "every-day-emergency" location lighting (http://photography-on-the.net/forum/showthread.php?t=66358)

Depth of Field (http://photography-on-the.net/forum/showthread.php?t=306018)


Depth of field and aperture selection question. (http://photography-on-the.net/forum/showthread.php?p=2407876)

[EOS_JD]

Getting everything in focus with groups can be difficult. If you have a straight row of people in front of you, not everyone will be the same distance from the camera. Think of a peice of string placed outwards from the camera with a pencil attached at the end. In your mind, draw an arc outwards and if people are placed along the line of the arc they will all be equidistant from the camera and therefore if you focus on any one, they should all be in focus.

To get larger groups in focus, use of smaller apertures helps. Small apertures means greater depth of field. Use of a wide lens too will mean greater dof and finally the distance you are to the subjects will also influence dof (further away = greater dof).

Shoot larger groups therefore with a wider lens (maybe 24mm)
Shoot at an appropriate distance
Shoot with a small aperture (f8 or smaller depending on lens/distance)

Use of a depth of field calculator will help to determine how to get everyone in focus also.

Lowest ISO that allows a suitable shutter speed should be used. ISO does not affect focus but can mean more noise.

[DD974]

Getting everything in focus with groups can be difficult. If you have a straight row of people in front of you, not everyone will be the same distance from the camera. Think of a peice of string placed outwards from the camera with a pencil attached at the end. In your mind, draw an arc outwards and if people are placed along the line of the arc they will all be equidistant from the camera and therefore if you focus on any one, they should all be in focus.

Thanks...that said, would this make sense to get everyone in focus......today I have a basketball team shoot and if I were to position the team in a slight arc and using my 50mm 1.8 on a tripod, focus (AI Focus, center point) on one of the players on either end, then recompose the shot to include the entire team.

[SkipD]

Thanks...that said, would this make sense to get everyone in focus......today I have a basketball team shoot and if I were to position the team in a slight arc and using my 50mm 1.8 on a tripod, focus (AI Focus, center point) on one of the players on either end, then recompose the shot to include the entire team.I don't think that makes sense at all without actually verifying the results through the viewfinder.

This is really one situation where manual focus makes a lot of sense. Actually, I would strongly suggest using manual everything to control the situation.

Stop the lens (aperture) down as far as you can while maintaining a usable shutter speed. If everybody is standing still and you are using a solid mount (tripod, ball head screwed to the top of a ladder, etc.) you should be able to get away with some fairly long shutter speed times and still have a decent image.

Manually focus and then use the depth-of-field preview button to get an idea of how much of the group would be in adequate focus at any particular setting. Using manual focus, you can see if you can have one focus position that is adequate for the whole group or you can find out where (on the group) the optimal focus should be to have the best result with depth-of-field helping you out.

[DD974]

Manually focus and then use the depth-of-field preview button to get an idea of how much of the group would be in adequate focus at any particular setting. Using manual focus, you can see if you can have one focus position that is adequate for the whole group or you can find out where (on the group) the optimal focus should be to have the best result with depth-of-field helping you out.

Thanks Skip, I've not tested that idea either, just thinking out loud. I just took a few shots with my 50mm 1.8, all manual (focus and settings) iso 100, the SS varied from 1/6th to 1/25th, F1.8....all handheld because I don't have my tripod or monopod with me at the moment.

Anyway...the lighting is somewhat dimmer than I'd like for this test and it's primarilly flourescent and ambient from a large glass window (overcast outside), the lights are prob. 20-25 above.

I chose a place in the room that had a corner so there'd be objects at variable distances from me. I manually focused, shutter button halfway, then pressed held the DOF preview button on my 30D (this should lock in the exposure, right) and the best image was 1/6th SS. I didn't see anything happen, was I supposed to, anything at the bottom of the viewfinder?, or does this happen w/o seeing anything displayed?

I guess I'm confused by what the book says, that is "press the DOF preview button to stop down to the current aperture setting". The part in bold threw me. Can you explain this a little better, I honestly just never used the DOF preview button, and have always just put the camera in the A-DEP mode when I toook group shots.

[E-K]

To me there is no appreciable difference in edge sharpness on the left (at least for the important bits). The right side however does seem to drop off a fair bit in sharpness. Have you tried this lens in better lighting conditions at the same aperture?

It does look like the camera wasn't completely parallel to the scene but I don't think it's enough to account for the difference.

In general I would pose and compose how you want the image and then use DoF to ensure everyone's in focus (see http://www.dofmaster.com for example).

e-k

[Curtis N]

The "plane of focus" isn't a flat plane. It's a curve. I would like to see a reference to support that statement. At this point I'm not buying it.

Are you suggesting that if I aim the camera straight at a brick wall such that the sensor plane is parallel to the wall, and focus on the bricks in the center, will the bricks closer to the edges be out of focus?

From everything I've read, the fact that the focused area is a flat plane is the reason the focus-recompose technique sometimes fails. The edges of the plane are further away from the camera than the center.

[E-K]

Hi Curtis,

The focus-recompose technique fails because the distance from the sensor to the subject changes when you recompose so it doesn't really matter whether the focal plane is flat or curved, you will get the same issue.

A macro lens may be corrected to ensure a flat field because it's more noticeable in these cases. To be honest though I don't think the OP's issue is due to a curved focal plane.

e-k

[Curtis N]

The focus-recompose technique fails because the distance from the sensor to the subject changes when you recompose so it doesn't really matter whether the focal plane is flat or curved, you will get the same issue.Generally focus-recompose is simply a matter of re-aiming the camera without significantly changing its position.I don't think the OP's issue is due to a curved focal plane.I don't think so either. A multi-row group shot is going to require significant DOF either way. I was just challenging Frank's statement.

Here's an article (http://visual-vacations.com/Photography/focus-recompose_sucks.htm)on my side of the argument.

[canonphotog]

I guess I'm confused by what the book says, that is "press the DOF preview button to stop down to the current aperture setting". The part in bold threw me. Can you explain this a little better, I honestly just never used the DOF preview button, and have always just put the camera in the A-DEP mode when I toook group shots.

The DOF preview is a useful tool but it takes some getting used to for those that have never used it before.

When you are looking through the viewfinder on a 50mm f/1.8 the aperture is always at f/1.8 until you take the picture. Then the aperture changes to your desired Av setting. If you are in Tv, the camera picks the aperture for best exposure for your selected shutter speed.

If you are in manual or Av mode and set the aperture to f/16, then press the DOF preview button, the viewfinder will darken appreciably. Depending on the light you have available it may darken enough that you can't see much through it. To see it's effect and better understand what it is showing you, set the aperture to f/8 and try again. Ignore the darkening viewfinder, what you are looking for is a change in focus of your image. With the DOF preview pressed you should be able to see that more of your subject is in focus.

To make optimum use of the DOF preview button for what you are doing, you should use a tripod and manual focus. After you learn to see what is actually going to be in focus during the exposure, you press the DOF preview button and while holding it down, adjust your focus manually until the object/person closest in the image is in focus and the object/person farthest is in focus.

If you can't get both the closest and farthest object/person in focus you stop down another step and check again. Note I said step not stop. How much this changes will depend on whether or not you have your stops set on 1/3rd or 1/2 stops.

A-Dep simulates this manual use of aperture and the DOF preview button. That said, Since I'm comfortable using the DOF preview button w/manual focus I've never used A-Dep.

You can use DOF calculators to help ensure that you have a wide enough band of focus for your needs. A tape measure will help if you choose that method. You will still have to adjust the calculated point of focus to optimize the location of the front and back of the focus zone.

Hope this helps you out.

[E-K]

Generally focus-recompose is simply a matter of re-aiming the camera without significantly changing its position...

Here's an article (http://visual-vacations.com/Photography/focus-recompose_sucks.htm)on my side of the argument.

I've read the article before and the diagram, to me anyways, is a little misleading. I think this diagram shows a little more clearly what is happening. If you replace the straight line (focal plane) with a curved one you can see my point that having a curved focal plane doesn't negate any issues with focus-recompose.

[Edit: to clarify, the diagram in the article is misleading for the purpose of discussion of flat field versus curved field, it makes sense in the context of the article itself and it's explanation.]

e-k

[Glenn NK]

I would like to see a reference to support that statement. At this point I'm not buying it.

Are you suggesting that if I aim the camera straight at a brick wall such that the sensor plane is parallel to the wall, and focus on the bricks in the center, will the bricks closer to the edges be out of focus?

From everything I've read, the fact that the focused area is a flat plane is the reason the focus-recompose technique sometimes fails. The edges of the plane are further away from the camera than the center.

I'm not buying it either. In fact one of the tests done on lenses on photozone is to determine if the plane of focus is in fact a flat plane. It's supposed to be in a well designed lens.

And your comment about focus/recompose supports this.

Thanks Curtis for mentioning this.

I just read on another thread that IQ was subjective - really? Then what are MTF charts for? There are also objective tests for contrast and vignetting.

http://www.imatest.com/docs/sharpness.html

[E-K]

And your comment about focus/recompose supports this.

I'm not seeing how the focus/recompose supports the argument that all lenses are flat field?

Lenses need to be corrected for a number of things and a flat field is one of those things. For most applications I wouldn't worry about it too much with a modern lens.

This is a somewhat interesting read on the subject: http://www.wisner.com/myth.htm.

e-k

[DD974]

Thanks for the explanation CanonPhotog, much appreciated.

[Glenn NK]

I'm not seeing how the focus/recompose supports the argument that all lenses are flat field?

Lenses need to be corrected for a number of things and a flat field is one of those things. For most applications I wouldn't worry about it too much with a modern lens.

This is a somewhat interesting read on the subject: http://www.wisner.com/myth.htm.

e-k


Not all lenses are flat field; that's one of the potential weaknesses of lenses.

It's my understanding that one of the criteria for lens design is a flat field, but lens design being a balance or trade-off of competing criteria, not all criteria are met to perfection.

It's standard procedure in lens testing to use a perfectly flat target that fills the entire frame, and is aligned perpendicularly to the axis of the lens. This will provide a check for flatness of image plane.

Sometimes the "brick wall test" is used; which will also yield results on distortion in addition to flatness of the plane of focus.

[E-K]

Not all lenses are flat field; that's one of the potential weaknesses of lenses.

It's my understanding that one of the criteria for lens design is a flat field, but lens design being a balance or trade-off of competing criteria, not all criteria are met to perfection.

Okay, and that's basically what I said ;)

But, what I asked was,

I'm not seeing how the focus/recompose supports the argument that all lenses are flat field? ...
e-k

To me the issue with how well corrected a lens is for a flat field has little to do with the issue you may experience when using focus/recompose. So can you tell me what you believe is the connection between the two?

e-k

[Glenn NK]

Okay, and that's basically what I said ;)

But, what I asked was,



To me the issue with how well corrected a lens is for a flat field has little to do with the issue you may experience when using focus/recompose. So can you tell me what you believe is the connection between the two?

e-k

I was agreeing with the comment by CurtisN. Because of the (nearly) flat plane of focus, focus/recompose will fail.

With a flat field of focus, focusing on the person at the edge of a group that was in a straight line perpendicular to the intended line of sight, and then aligning the camera to the centre of the group, no one would be in focus with a very shallow depth of field.

With a flat field of focus, focusing on the centre, will put them all in reasonably good focus; however if the field of focus is curved, then the edges start to fall out of focus.

If the group was aligned in a curve so that everyone was equi-distant from the camera, then it wouldn't matter where the point of focus was.

Perfect lenses have a flat field of focus; I'm still looking for perfect. However, I have some good ones.

[E-K]

I was agreeing with the comment by CurtisN. Because of the (nearly) flat plane of focus, focus/recompose will fail.
...Perfect lenses have a flat field of focus; I'm still looking for perfect. However, I have some good ones.

Ah, okay. I re-read the thread, and specifically EOS_JD's, and I can see where you are coming from. If the subject surface that creates a flat focal plane is the portion of a sphere with the camera in the centre of the sphere, then yes focus/recompose would by definition not be a problem.

Really that's a specific case and not the general case which is why I was confused...well that and I need some sleep ;).

You can still have a lens that exhibits field curvature for which focus/recompose would still be a problem (e.g. where the radius of the subject surface sphere is larger than the focus-point to focal plane distance).

e-k

[Glenn NK]

You can still have a lens that exhibits field curvature for which focus/recompose would still be a problem (e.g. where the radius of the subject surface sphere is larger than the focus-point to focal plane distance).

e-k

Absolutely correct - and perhaps the reason lenses aren't designed to have a curved (spherical) plane of focus. Going from a flat surface to a flat surface (the film/sensor) would be hard enough, but getting a perfectly spherical surface to match a flat focal plane might be an optical design nightmare. Just speculating as I'm definitely not up on optics.

The only curved sensor I know of is the human/animal eye, but that seems to be to keep it compact and so it can rotate in the eye socket.

[E-K]

There are some examples of curved sensors - Schmidt Cameras comes to mind - but it certainly isn't common.

e-k

[Glenn NK]

There are some examples of curved sensors - Schmidt Cameras comes to mind - but it certainly isn't common.

e-k

I'll bet they cost a fair bit more than flat ones. Never heard of Schmidt before.

[E-K]

The sensor in this case would be film or a plate - sorry I should have been more explicit - so the cost isn't too bad compared to the flat ones ;).

A Schmidt Camera (http://en.wikipedia.org/wiki/Schmidt_Camera) is used in astrophotography.

e-k

[suecassidy]

Yikes. My eyes are beginning to bleed from following this thread. Did the question ever get answered? I'm too overwhelmed to be certain if it has or not.... : )

[marcus769]

Try a bigger aperature first, and yeah a different flash angle would help greatly!

[canonphotog]

Yikes. My eyes are beginning to bleed from following this thread. Did the question ever get answered? I'm too overwhelmed to be certain if it has or not.... : )

Yes. I answered it.

[E-K]

Yikes. My eyes are beginning to bleed from following this thread. Did the question ever get answered? I'm too overwhelmed to be certain if it has or not.... : )

To be honest I don't think either the OP or dcyphert's first questions were ever completely answered ;).

e-k

[DD974]

Bump....

I am hoping someone can help me here with advice.
Can anyone give me some sound advice on getting a tack sharp group photo?

Ok...so far since my original post I understand a larger aperture would probably helped...and I know that the distance from the group and the number of rows factor in too. I don't know if I read it here, but a post I read recently said as a rule of thumb would be to use f5.6 for one row, 8.0 for two and 11 for three....I also read somewhere that modern std. lenses having 6-7 elements achieve the sharpest results at f5.6-f8.0 and older lenses with 4 elements should use f11.0 for sharpness. I'm just not sure if I just might have a bad copy of the nifty-fifty. I realize it's a cheap lens, but just expected better results overall after hearing all the accolades about it.

[E-K]

Bump....

I am hoping someone can help me here with advice.
Can anyone give me some sound advice on getting a tack sharp group photo?

Ok...so far since my original post I understand a larger aperture would probably helped...and I know that the distance from the group and the number of rows factor in too.

Basically, number of rows defines how much depth-of-field is required. The focal length you are using, distance from the subject(s), sensor/film size, and desired print size, combine to determine your depth-of-field.

I don't know if I read it here, but a post I read recently said as a rule of thumb would be to use f5.6 for one row, 8.0 for two and 11 for three....

Not familiar with that rule of thumb but for it to work it would need to make some assumptions about the other things that go into making up the DOF.

I also read somewhere that modern std. lenses having 6-7 elements achieve the sharpest results at f5.6-f8.0 and older lenses with 4 elements should use f11.0 for sharpness. I'm just not sure if I just might have a bad copy of the nifty-fifty. I realize it's a cheap lens, but just expected better results overall after hearing all the accolades about it.

According to the test on photozone.de, the 50mm MKII is sharpest around f/5.6. That being said, it's pretty sharp all around, being a little softer wide open.

Do you have a sample of an image taken with the 50mm that you think should have been sharper that you can post?

e-k