I have that issue with my 50mm since I tend to use it for low light shots and have the aperture on f/1.4.
I find that with the 50mm, even though it feels in camera that I have focussed on some specific part of the frame, the shot turns out with it focussing on the wall behind or slightly to the side of the person or subject of the shot. Most annoying.
Here's a good tip on aperture and DOF Ad astra per aspera
Then there is the fact that those detectors (captors maybe?) are about contrast values and that they are big enough in size to choose in the bracket area the "best" contrast, meaning the easiest, to focus on.
If you center the bracket on a limit between a fuzzy or dark material and a grouted well lit wall, it'll choose the wall !
Now if you combine the facts that the AF captors aren't exactly where you think they are, added to the "easy" contrast values, you'll find yourself with "accidently" focusing on parts of the scene you didn't choose yourself ! Some will claim they have front or back focusing problems (it happens and is repaired easily) when in most cases it's because of those AF captor sizes and targets...
While in manual focusing, you have the matted screen, but also the little green focusing light (lower left in the viewfinder). My own observation, backed by quite a number of other photographers is that this light has several states: not lighted (not in focus), lighted in full (in focus)... And flickering before "full" or after !
I have the sharpest focus when having the flickering green light before full light when focusing from close range toward infinity. While I use old MF lenses with a longer focusing throw (meaning I can be very precise between flickering or not), it seems it works also with AF lenses with a shorter throw (it's just harder to get to the precise point)...
If one day you discover you're fond of manual focusing a Katz-eye viewfinder glass replacement (not cheap but not needing any mortgaging the house either), it will allow you to use the stigmometer focusing screen all old SLR's used to have :-) Those who have eyesight problems and prefer manual focusing just rave about it !
I still rely on the original viewfinder glass, but might change in a few years ! "What can I do, What can I write, Against the fall of Night". A.E. Housman
More tips for me to follow! Thanks. Ad astra per aspera
With a digital camera like the D80, the ratio of the CCD is about 1.5 compared to 24x36 (or 135 format). That means that when set at 50mm focal (for example), the 135 equivalent (or apparent) focal length would be 75mm.
The old trick of trade, stating that you have to set your speed at least at the focal length value (1/50th or 1/60th for a 50mm lens) seems to apply with the so-called crop factor (1.5). That's for camera motion blur vs the subject motion blur !
At the tele end of your zoom (105mm) you should be at a speed of 1/200th (1/157th)if hand holding or use a tripod for slower speeds.
I'm sure that, looking at the exifs, you'll find you have a higher rate of sharp pictures at the wide end then at the tele one... :-)
Then you have the aperture (or f stop). Setting it wide open (small number) allows for more light or a lower speed value in a given light... But it reduces you depth of field (or DoF), meaning that the plane of sharpness is quite shallow ! Add that problem to an auto-focus or manual focus a bit too near or too far and you get a seemingly not so sharp picture !
Of course, all that is above is for a given ISO value (the good old film ISO/ASA number). But with the D80 you can add ISO as another variable by changing it or allowing it to change automatically with auto-ISO.
You can try a "false" manual setting... You get in auto-iso mode, in manual mode, you set a speed value, fixed high enough for your lens crop factor. You then forget about it and use your camera as in mode A (aperture priority), setting the f stop in relationship to DoF.... Then take the pictures ! Auto-Iso will adjust ISO value accordingly, setting it higher if the scene is darker or lower if the scene is lighter... It has some limitations though. The higher you go with ISO, the more you are prone to "noise" (or digital grain), and you can't go much lower then 100 ISO (if it hits the floor, you'll have to act on speed or f stop)!
Does this helps ? :-) "What can I do, What can I write, Against the fall of Night". A.E. Housman
Great reply... And quite to the point :-) (Maybe that's why I don't teach photography)!!! "What can I do, What can I write, Against the fall of Night". A.E. Housman
Ask for explanations of the other jargonese in there!
Really: I'll wait.
The closer you hold the hole, the more you can see of the scene, the further away, the less you see. So, short focal length means a wider angle view, long focal length means narrow angle view.
To illustrate the effect, I'll demonstrate why I do photography rather than drawing: on the left we have a pinhole very near the sensor, so the tree(!) only occupies a small part of the frame, on the right the pinhole is much further away, so the tree occupies lots of the frame.
So far so good?
Now, where this gets interesting is when you change the size of the sensor the light is falling on:
Three sensors indicated there, for a 60mm focal length: 35mm, the DX sensor in the Nikon digitals and most other digital SLRs and 6x6 film. Digital compacts have much smaller lenses.
If you trace the light you can see that the "house" (or "robot") is covering most of the 6x6 frame, that only a small part of it is visible to the 35mm sensor and even less to the DX sensor. A compact camera thinks that a 60mm lenses is a long telephoto while a 6x6 sensor sees it as a normal lens and a 4" x 5" would see it as an extreme wide-angle. Thus the 60mm lens on a 35mm is equivalent in angle of view to a 90mm on the DX sensor.
DId that help?
More seriously, great effort, you must have a scan nearby ! Next step: perspective (or the face you don't recognize with that big nose in the middle :-) )... Or why it is independent of the focal length but in direct relationship with the distance between the subject and the film plane (or captor, or CCD)...
The fact, as shown in Colman's drawings, that different focal lengths (i.e. the usual lens naming) gives you different viewing angles is often confused with the "perspective" effect (the too big nose). Most people think that with a wide angle you have a "bad" portrait, while with a mid-tele that's not a problem...
As in the drawings above, we tend to "fill" the frame for a portrait (just an example), so with a tele we are at some distance of the subject, while with a "wide-angle" we would be much nearer, thus accentuating the perspective effect.
It works with buildings too, when people want to get the whole church "in the frame" they often favor a great wide-angle lens increasing the weird feeling that parallels spires are meeting in some not too far points !
When you don't have the backing space for a "frame filling" shot (often the case in old cities) it is often easier (i didn't say better) to find a distant viewpoint (the hill outside the village ) and to use a big tele lens...
Or to use your ordinary lens (35m or 50mm) and frame part of the church in a way that conveys the feeling you had when seeing it (the church). :-) "What can I do, What can I write, Against the fall of Night". A.E. Housman
Or to use your ordinary lens (35m or 50mm) and frame part of the church in a way that conveys the feeling you had when seeing it (the church). :-)
As in gioele 's Prague picture below :-) "What can I do, What can I write, Against the fall of Night". A.E. Housman
Isn't that two separate issues? The face distortion is due to the way it's spread over the frame (compared to how we expect to see it - you can get the same effect by eye if you pay attention to what you're actually seeing), while the meeting spires is more to do with the sensor plane not being vertical - you point it up at the church and that causes distortion.
That's why view cameras can correct for it: you can set the back parallel to the subject and use the front movement to get the framing you want:
From Ansel Adam's The Camera.
The face distortion is about distance and as you say you can see it if you get near the subject's nostrils :-)
But for a given distance, a tele shot and a wide angle shot will generate the same perspective deformation if you superpose the two pictures (blowing one up or shrinking the other)... "What can I do, What can I write, Against the fall of Night". A.E. Housman
I just came back from a sudden trip from Finland; have I missed much? You have a normal feeling for a moment, then it passes. --More--
perspective (or the face you don't recognize with that big nose in the middle :-)
The folks I know who do portraits on a regular basis swear that 100mm to 135mm (35 mm cameras) lenses are the best for such work--just to avoid the problem you mention.
These lenses also mean that you can get detailed shots without getting too close to the subject. "Remember the I35W bridge--who needs terrorists when there are Republicans"
For portraits - in the sense of a depiction of a person - that include the environment you can use much wider lenses without making the person look too scary. It's all a matter of how much of the frame they're filling.
This is helpful, thanks. I will have to read over everything again when I am not supposed to be working! Ad astra per aspera
One thing I found in an article - and verified myself experimentally - is that this particular lens reaches a max sharpness at f/2.5. Below that it is noticeably less sharp. The spendier f/1.4 50mm is at max sharpness throughout the aperture range.
I'm really appreciating the VR on my zoom lens after working with the new one. It's really tough to get decent low light shots even at f/1.8 that don't exhibit a fair bit of camera shake.
you are the media you consume.
(We have both the AF-D one and a much older manual version.)
Having less of the picture in focus is actually an advantage. Look at my picture of a bottle on a mountain background below; it's out of focus on purpose.
I usually have it set all the time, except in twilights where it will light more a scene then I want it, making a full day shot of an almost night scene. "What can I do, What can I write, Against the fall of Night". A.E. Housman
