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I'm shooting a banquet room restaurant for website pitures and am having trouble getting the enitre room in focus. The shots Ive taken theres one set table in focus and the glasses and decor on the other table are really out of focus. How can I get everything in focus? I'm shooting with a Mark3 5D and lenes Ive used...70-200 mm 1.2, 50 mm 1.2,85mm 1.2, amd 24-105mm, Can someone please help me with settings and the best lense to use?

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Significant depth of field typically requires a narrow aperture. Narrow apertures require longer exposure times. Longer exposure times require a tripod. Alternatively, a higher ISO can be used in lieu of longer exposure time but will often reduce image quality by increasing the noise.

For a banquet scene, using the wide angle 24mm of the 24-105 at f16 puts the hyperfocal distance at approximately 1.3m (4'-0"). Focusing on an object at this distance will place all more distant objects in reasonable focus when the lens is zoomed to 24mm. The light level of a banquet hall is probably between Ev_100=6 and Ev=100=9 suggesting that 7 to 9 stops of shutter speed and/or ISO will need to be added from shooting in full sunshine at (ISO 100, 1/125 sec, f16). See the Sunny 16 rule.

Note that longer focal lengths have more distant hyperfocal distances at a constant aperture. For example the hyperfocal distance at f16 for a 100mm on the 5D Mark III is about 20m (70 feet).

Nine stops of shutter speed from 1/125 second is a four second exposure. Seven stops is a one second exposure. Without a tripod the results of such long exposures are likely to be unsatisfactory.

Nine stops of ISO from ISO = 100 is ISO 51200. Seven stops of ISO is 12800. These are achievable on the 5D Mark III but you will probably not like the results due to the noise level.

Adding supplemental lighting is an alternative, but creating a proper exposure will be more technically complex than using the ambient light and is best done with photographic lighting equipment.

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Your issue is, how do I obtain the necessary depth-of-field to accomplish this task? Depth-of-field is that zone, before and after the point focused upon, that will be rendered acceptably sharp. The zone of depth-of-field contracts or expands based on a. the lens aperture b. the distance we are focused upon c. the focal length of the lens. d. the display size of the final image, viewing distance, and visual acuity of the viewer.

You can expand this zone by closing down the working diameter of the lens. We are talking about using a tiny lens aperture like f/22 or f/16 or f/11. The f/22 setting delivers the widest depth-depth of field. Likely the banquet hall is large and you will need an expanded depth-of-field. To accomplish you focus, not on the middle of this expanse. Instead, focus on a point about 1/3 back towards you from the middle. This works because the zone of depth-of-field extends further to the rear then forward of the point focused upon. Now that you are focused at about a distance 1/3 into the view, use a setting called aperture priority. This setting allows you to select the aperture that will be used. This setting freezes the selected aperture. To get the exposure correct, the camera logic will not alter the shutter speed to accommodate your pre-set aperture.

Because the end result shutter speed will likely be quire long, you should mount the camera on a sturdy support such as a tripod. Your best bet is likely f/22 or f/16 however; you should shoot a series at different aperture settings at different focusing distances. The key here is, depth-of-field extents 1/3 back towards the camera and 2/3 behind the point focused upon. You should also experiment elevating the ISO setting. Higher ISO allows smaller aperture with a corresponding faster shutter setting.

Also in this balance is the focal length of the lens. The shorter (more towards wide-angle) setting will yield the greatest elongation of depth-of-field.

Best of luck to you.

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  • The 1/3 - 2/3 (1:2) ratio of DoF is only true at a specific focus distance for any given focal length and aperture. Focus very closely and it approaches 1:1 focus at the hyperfocal distance and it is effectively 1:∞. – Michael C Oct 24 '17 at 22:16
  • @ Michael Clark - The 1/3 - 2/3 rule of thumb is generally valid for this type of subject. Rules of thumb are a good way to teach to a non technical audience. – Alan Marcus Oct 24 '17 at 23:10
  • I disagree that the 1:2 rule of thumb may be applicable here. If the nearest table is three feet in front of the camera and the furthest one is 100 feet it certainly would not be. At 16mm on APS-C and f/8 a focus distance of 14 feet (or less) would be needed to get everything from 3 feet to infinity in focus. The ratio of 11:86 (1:7.8) is far from 1:2. If the photographer focused at 33 feet for a 100 foot room anything closer than 3.43 feet would not be acceptably sharp. The nearest 5-6 inches of the table, which is what our eye-brain emphasises the most, would be noticeably blurry. – Michael C Oct 25 '17 at 0:15
  • @ Michael Clark -- Why don't you tell him to use the 24mm set to f/16 focused at 10 feet? – Alan Marcus Oct 25 '17 at 0:30
  • 7:90 (1:12.8) is not 1:2 either. Your 1/3 + 2/3 comment would place the focus distance at 33 feet in a 100 foot long banquet hall. F/16 is quite a bit past the DLA of most APS-C cameras as well. They tend to start showing effects of diffraction at around f/7. – Michael C Oct 25 '17 at 3:13
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Like Alan Marcus said in his answer, you will get the largest area in focus by focusing one third into your frame. I'd advise you to use this technique and avoid using very small apertures like f/22, because generally after f/11 most cameras will start showing diffraction very clearly.

Diffraction happens when the light starts bending when it goes through the small aperture and blurs enough to scatter on to different photo sites on the sensor. This causes the image to get less sharp.

Diffraction will be more prominent and occur sooner (at a larger aperture) on a more pixel dense sensor. You can read more about diffraction here: https://photographylife.com/what-is-diffraction-in-photography

Diffraction won't ruin your photo, but knowing about it is valuable.

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