70-200 F2.8 IS

[martindomok]

<p>Hello,<br>

I have a question regarding the F number.<br>

Yesterday I was taking some portraits of a couple - informal portaits and I shot 2 ppl at F2.8, when they were not in the same level, one of the couple was out of focus, what F number do U recommend in such case?<br>

F 4? F5.6?<br>

At that particular location, it was getting dark and I needed to shoot at F2.8<br>

Thanks,<br>

Martin</p>

 

[william-porter]

<p>Martin,</p>

<p>No way to answer your question without more info. Distance from the subject is as important to depth of field as the f-number, perhaps moreso. If you were five feet from 'em, f/2.8 might provide very shallow depth of field. If you were 20 ft away, f/2.8 might provide adequate depth of field. Some people seem to be able to figure this out using the depth of field preview feature on their cameras. I don't find that very helpful. I either know from experience what will work or I shoot, then review on screen and enlarge to check for decent sharpness where it matters. </p>

<p>If it gets dark, you have options other than opening the aperture. You can slow down the shutter (very reasonable for portraits, if you can get the subject to sit still), or you can increase the ISO, or you can supplement the light with a flash. </p>

[mendel_leisk]

<p>Very likely your camera has a depth of focus preview button. I'd suggest to experiment with it, see what various f-stops do. It's not really practical to use this when shooting, if your subjects are moving around, etc.</p>

<p>Pushing this button will also darken the display, but gives you a feel for what the depth of focus will be.</p>

[martindomok]

<p>William, indeed, I shot at 135mm and the distance was about 6 meteres.<br>

I have been noticing that Depth of field button since 2003, but have never used it.<br>

How does it work? I know that when U press it the lens kinda freezes and then it comes back to original, what shall I look for? Or read the manual? I guess. If only I knew where it is...<br>

Yeah, zooming would be an option, but I try not to use the flash with my long lesn - 70-200, especially from longer distances.<br>

Yeah, pumping up the ISO would be the oprion of course, but I didnt want do that and kept it low.<br>

Mendel - so U hit depth of field button and see. Trying different F numbers and pressing again... gosh I feel so dumb now as I have never used this feature before.. anyone else using it a lot?<br>

Thanks,<br>

M</p>

 

[neilambrose]

<p>If you're shooting at 2.8 on a lens where the maximum aperture is 2.8 then you don't need depth of field preview. What you see on the focusing screen is what you'll get, as your lens focuses at maximum aperture. If you want multiple subjects in focus at maximum aperture then they need to be on the same plane. You can generally judge this in the viewfinder by eye. If you can't get them on the same plane then you need to alter your position to them, so that you're on an 90 degree intersection with an imaginary line you draw between them. (Think triangles).</p>

<p>Otherwise, look for some kind of support and stop down a couple of stops.</p>

[mark_t5]

<p>dont really use the dof preview button. i can pretty much assess whether the F number i use will have what i want in focus or not.</p>

<p>crank up the iso if you have to man, a crappy shot is better than no shot.</p>

[martindomok]

<p>Mark true, with 40D is pretty good even at 800 or 1000 ISO...<br>

I should have done that, anyway, shot tons on that location and I will need just 2-3 images from that spot.</p>

 

[picturesque]

<p>It is hard to see the DOF in the viewfinder using the DOF button, because the camera stops down to the working aperture (unless you have the case that Neil describes). Better would be to familiarize yourself with needed DOF for various situations. Even better would be to construct the DOF dial available from dofmaster.com. I have one, and it is great to use in the field.</p>

[William Michael]

<p><strong><em>“what F number do U recommend in such case?”</em></strong><strong><em></em></strong><br /><br />It took a long bit of time watching this thread to get all the information required to give a definitive answer . . . (we needed the camera format, too).<br /><br />MM: Depth of Field (DoF) for non macro shooting is dependent upon <strong><em>Focal Length</em></strong> of the lens used; the <strong><em>Aperture</em></strong> used; the <strong><em>Subject Distance</em></strong> and the <strong><em>Camera Format</em></strong>.<br /><br />For a <strong><em>40D</em></strong>; <strong><em>135mm lens</em></strong>; and a <strong><em>Subject Distance of 6mtrs</em></strong> (about 20ft), if one Person were behind the other with shoulders near touching and both just about square on to the camera, we could assume that two Persons of average build will make a Subject about <strong><em>24inches (2ft) deep</em></strong>.</p>

<p>(at 20Ft with a 135mm on a 40D you would be pulling a tight bust-shot vertical or an half-shot horizontal).<br /><br />The Photographer would need to use <strong><em>F/8 as the largest aperture</em></strong> in that scenario: <strong><em>F/11</em></strong> would be <em><strong>much safer.</strong></em><br /><br />At F/11 it would be reasonably safe to focus on the cheekbone of the person farthest from the camera.<br /><br />WW<br>

Post Script: <strong><em>"Better would be to familiarize yourself with needed DOF for various situations." </em></strong><br>

<br>

Agree 100%. <br>

<br>

It doesn't take long to memorize three DoF for three key F/stops and three key distances for three lenses . . . we only used to use three lenses :)<br>

that's only NINE numbers to remember . . . <br>

hardly even a modern day telephone number . . . <br>

next we can get onto remembering <strong ><em >manual flash fill</em></strong> apertures and their distances :) <br>

</p>

<p > </p>

 

[martindomok]

<p>Gotcha, also, what I could have done: <br>

Shoot that couple next to each other shoulders pressed together, shoot F5.6, then at 8.0 and at 11 and compare results, easy, that works for me the best - compare results and pic the best, if there would only be F bracketing, in this case shooting RAW would be the best. <br>

But Im surprised the F11 would be safe, I rarely shoot people/portraits at F11, to be honest, almost never, but this was a fantastic learning opportunity for me. William thank you for your input!<br />Have a good day, <br /><br />Martin</p>

 

[martindomok]

<p>Nadine just checked the dofmaster.com<br>

It is fantastic, I have read about different DOF, when using different focal lenghts and F numbers, but that wa slong time ago! <br>

Still I remember the picture, did some online calculation and William was right F8.0 would be just right!!!</p>

 

[fotografz]

<p>This is the problem with many modern AF lenses ... the Depth of Field scale on the aperture ring is missing .... because there is no aperture ring at all.</p>

<p>What you see on the focusing screen even when pressing the DOF button can be misleading ... what may look sharp that small won't be when you open the file at computer screen size and try to print it.</p>

<p>If shooting formals where you have a minute to check focus, then do it on the camera's LCD screen. You can zoom in 10X on a test shot and scroll front to back side to side to make sure everything is in focus. If you are in a hurry, then checking anything on the camera is a moot point and it's better to stop down to f/5.6 or f/8 depending on focal length and distance to subject.</p>

<p> </p>

[William Michael]

<p> <strong><em>"But Im surprised the F11 would be safe, I rarely shoot people/portraits at F11, to be honest, almost never, but this was a fantastic learning opportunity for me</em></strong>."<br>

<br>

I am glad my comment was not misinterpreted.<br>

I noted this: <em>"anyway, shot tons on that location and I will need just 2-3 images from that spot." </em>and it made me shudder.<br>

IMO it is better to know the parameters before hand, than "spray and pray"<br>

FWIW, below is one of my two "Bibles" which I always carry. It has survived dunking in the sea, and also D76 . . . it is the 1975 version (first edition) of the Kodak Professional Photoguide - pp 29 & 30 have DoF for normal, wide and tele lenses: note p31 has a table of shutter speeds for stopping motion - including people sitting or "standing still" – a topic often mentioned on this forum in relation to Brides and Grooms at the Altar.<br>

<br>

WW <br>

<br>

<br>

</p>

<p > </p>

<div></div>

[martindomok]

<p>Will not at all misinterpreted :) <br>

Much appreciated!<br>

Better have knowledge and be confident what U r doing than just spray and pray.. <br>

Charts for ppl sitting and standing, how charming ;) </p>

[wedding-photography-denver]

<p>Some of your question is answered by the distance you are from your subjects, that is one aspest that is often left on the shelf when photogs are talking about DOF. F2.8 is plenty deep when you are 100' from your couple, but not at 6'.</p>

[martindomok]

<p>Yes, I knew that but never atually wanted to know the numbers, now calculated on dof websote Im very clear.</p>

 

[mt4x4]

<blockquote>

<p>Old DoF tables - still very useful</p>

</blockquote>

<p>Expodisc sells these new. They are just the dial portions, but you flip them over and get the other char. They are very very handy, especially for landscape work. And only like 20 bucks.</p>

[ben_goren]

<p>There're two more numbers to know when considering depth of field: print (enlargement) size (taking into account cropping) as well as intended viewing distance.</p>

<p>Even without seeing the images in question, I can state with a great deal of confidence that you've got adequate DOF in your original picture for a postage stamp, and even at f/11 you probably wouldn't have enough DOF for a 30" x 40" print viewed from 6" away.</p>

<p>Cheers,</p>

<p>b&</p>

[martindomok]

<p>yesterday I shot this even, inside shooting, 40D, I knew I would be suing only one lens 16-35 F2.8 so I checked the DOP on line prior the event and decided to shoot at F8.0. Very unusual F number for ppl in this region at party events like this, everyone mostly uses F5.6. <br>

All these shots I take are usually anywhere between 1-3 or sometimes 4 meters away. <br /><br />Shooting at F8.0 takes power of the batteries quickly, I ended up shooting at F5.6.<br>

Checked pictures in the PC just now. F8.0 worked well, deleted about 10 percent of shots out of 150 and other results are just fine. <br /><br />Sending a sample at F8.0<br>

Girl's eye closer to the lens is out of focus, also dude is not at his sharpest...<br>

Good enough for a small pic in the mag.</p>

<p> </p><div></div>

[surfidaho]

<p>Howdy!</p>

<p>F8 Is Great. Shooting groups at f2.8 is asking for trouble. Go at least F5.6. Use a flash if you have to.</p>

<p>Later,</p>

<p>Paulsky</p>

[picturesque]

<p>Two things. First, where you put the focus point is important. For most lenses, putting the plane of focus 1/3 of the way into the depth desired in focus, makes the most efficient use of the DOF. Second, a cropped sensor camera like the 40D has about 1.3 stop 'more' DOF than a full frame camera. Actually there is a third point. Your latest sample shows that even at f8 and a wide angle length, if your subject distance is very small, you still don't have miles of DOF. You gotta consider all three factors and change accordingly. At receptions, I often change to f8 for table shots, just to be sure (I use a full frame camera).</p>

[martindomok]

<p>Nadine fair point, thanks again I learned a lot only withinh this thread!<br>

Have a great day,<br>

M</p>

[William Michael]

<p><strong ><em >"Girl's eye closer to the lens is out of focus"</em></strong><br>

<strong ><em > </em></strong><br>

Possible disagree - need to see a better resolution image for a definitive comment.<br>

<br>

The leading eye in a 1/4 profile is usually in the same plane as the top of bust / front of shoulder. If you look at the strap of the bag and the dress line, neither is “as out of focus” as the eye you reference.<br>

<br>

If you look at the background, where the flash fall off is maximum and also the outside where the sky is only slightly blown, we can conclude the room ambient is relatively close to the flash exposure – enough to give some exposure of the primary subjects.<br>

<br>

IMO you have subject movement, specifically the head of the female turning toward the camera and slightly upward as she is speaking, I do not believe we can conclude the right eye is OoF. <br>

<br>

IMO, it is more likely Tv = 1/100s was too slow for this shooting scenario. Better to use Flash sync at max Tv. or to use High Speed Sync.<br>

<br>

Also, following on from Nadine's comments - if the image is a full frame crop and the EXIF is correct you had: FL=16mm and SD = 3ft / 4ft. The DoF at F/8 would then be between 5ft and 13ft - so even if you shot at SD=3ft (DoF = 5ft) and the right hand AF sensor picked up on the man - there would ample DoF to get the woman in focus - (and it is apparent that you did not focus on the background) – so I think that adds weight to my theory of subject movement <br>

<br>

WW</p>

[martindomok]

<p>I focused on the girl and tilted the camera towards her, so the dude became OoF, that si what I think.<br>

I shot M, of course and there wansnt that much movement.<br>

I like that F8.0, however, shooting at F8.0 in a dark room eats up batteries pretty quickly.Will have to stock up - also I used an extra battery charger - from Canon, that plastic one that recharges the flash faster.</p>

 

[William Michael]

<p>You might be surprised how much movement, especially in the head (and hands) there is when the average person is "standing still"<br>

The slowest "safe" Tv for a B&G standing at the Altar, is 1/125s to 1/160s - that is without "timing the shot"<br>

Just some thoughts for consideration.<br>

WW</p>