focus problems.

amadeus

I normally shoot outdoors action with my (now)D700 and a couple of average lens and focus has been ok. I always use autofocus.

Been shooting indoors and figured it would be easier not harder to get good focus.

Took these Saturday with the D700 and 50mm F1.8 (prime?) lens. It is not a zoom straight 50.

Focus is not good at all.

Took this at F 3.5 shutter 80 ISO 320 and the center bike is somewhat focused but the left and right clearly are not.

amadeus

same day only difference is shutter = 60

center focus much better than sides.

pathfinder

You're right, the center bike is in focus, and the ones on either side are not in focus, just as I would expect at this close distance with a 50mm lens at f3.5 with a full frame camera.


Depth of field is a function of the distance from the image plane, the size of the optical sensor, and the aperture used, among other things.

You can read about depth of field on Wikipedia here - http://en.wikipedia.org/wiki/Depth_of_field

You can find a nice depth of field calculator here - http://www.dofmaster.com/dofjs.html There are DOF apps for the iPhone and the Droid as well.

I think your camera is fine, Amadeus. A full frame camera has a much shallower depth of field than a point and shoot. This can be an advantage, or a disadvantage depending on your needs and desires.

Step farther away, use a smaller aperture, use a smaller sensor based camera are all tricks to get more dof.

amadeus

so yesterday I ended up at B&H in manhattan, the superstore, (what a place) and the guy said, probably it was aperture. ok..went back today and retook the shot with higher aperture, F5.6, same lens.

focus still lousy.

amadeus

this also from saturday. I don't think ANYTHING is in focus as good as it should be?

F4.5

pathfinder

To really discuss focus issues, you need to put the camera on a tripod, focus on a flat plane surface like a newspaper or a brick wall perpendicular to the lens axis, use a remote shutter release, or a timed release, and see how the camera does. Hand held shots are really not ideal to determine focus errors.

The first shots look like depth of field issues as I said.

The later shots were all handheld. What were the shutter speeds for these image shot indoors in poor lighting?

There really is a reason one uses a tripod and a remote release if the images are not sharp. The most effective tool for sharpening unsharp images is a good tripod and a remote release. Once you have done that, if the images are still unsharp, then we can determine if the camera or lens is at fault. Not until.

A D700 does not have built in anti shake for a 50mm lens, unlike a lot of P&S. Point and shoots spit out sharpened highly sharpened jpgs. The D700 does not, unless you program it to do so.

amadeus

from today. F7.1

in all that distance from an elevated perch? nothing in focus?

amadeus

pathfinder wrote: »

To really discuss focus issues, you need to put the camera on a tripod, focus on a flat plane surface like a newspaper or a brick wall perpendicular to the lens axis, use a remote shutter release, or a timed release, and see how the camera does. Hand held shots are really not ideal to determine focus errors.

The first shots look like depth of field issues as I said.

thanks. I was thinking after speaking with the guy at B&H that to get the good results I need to go with higher # F stops and slower shutters and would therefore need a tripod but gees I thought this stuff would be a cakewalk...:cry

amadeus

pathfinder wrote: »

You're right, the center bike is in focus, and the ones on either side are not in focus, just as I would expect at this close distance with a 50mm lens at f3.5 with a full frame camera.


Depth of field is a function of the distance from the image plane, the size of the optical sensor, and the aperture used, among other things.

You can read about depth of field on Wikipedia here - http://en.wikipedia.org/wiki/Depth_of_field

You can find a nice depth of field calculator here - http://www.dofmaster.com/dofjs.html There are DOF apps for the iPhone and the Droid as well.

I think your camera is fine, Amadeus. A full frame camera has a much shallower depth of field than a point and shoot. This can be an advantage, or a disadvantage depending on your needs and desires.

Step farther away, use a smaller aperture, use a smaller sensor based camera are all tricks to get more dof.

thanks for the links and thanks for responding. awesome link on wikpedia.

amadeus

thanks again Pathfinder that DOF calculator link is really cool. I just can't believe that it is that critical. the guy at B&H, (again, what a place, there was a line of over ..75 people waiting to get in at 10 am) said he's seen where one persons eye is in focus and the other isn't. I thought shooting mx would have been harder compared to shooting ducks on a pond but...:bash

amadeus

one good one from today, I was asked to try some B&W and played around and for whatever reason ended up at F11.

much cleaner.

pathfinder

The D700 is a superb camera, wish I had one. It is easier to get snappy images from a P&S for several reasons... Greater DOF due to the much smaller sensor, anti-shake technology reducing blur from stabbing the shutter, short focal length lenses, and in camera processing to make image pop with contrast and sharpness.

But most full frame DSLRs require some care to get really optimal images. They are set up to yield soft, low contrast images, to allow one to post process in Photoshop for a final image. The images are sharp, but require some editing to bring them out. Try increasing both the contrast and sharpness settings in your menu in your D700. Keep your shutter speed above 1/100 handheld to start.

As DOF master will shot, f11 has much greater DOF.

Your color in your images is funky too, what was your white balance set at? AWB?

I think Nikon AWB usually is better than this, even under fluorescent lights. Were these lights Na Halide perhaps?

amadeus

pathfinder wrote: »

The D700 is a superb camera, wish I had one. It is easier to get snappy images from a P&S for several reasons... Greater DOF due to the much smaller sensor, anti-shake technology reducing blur from stabbing the shutter, short focal length lenses, and in camera processing to make image pop with contrast and sharpness.

But most full frame DSLRs require some care to get really optimal images. They are set up to yield soft, low contrast images, to allow one to post process in Photoshop for a final image. The images are sharp, but require some editing to bring them out. Try increasing both the contrast and sharpness settings in your menu in your D700. Keep your shutter speed above 1/100 handheld to start.

As DOF master will shot, f11 has much greater DOF.

Your color in your images is funky too, what was your white balance set at? AWB?

I think Nikon AWB usually is better than this, even under fluorescent lights. Were these lights Na Halide perhaps?

yeah those are strange lights. they aren't flourescent and take awhile to turn on and make a hum while they do. but yes WB was auto.

pathfinder

I wonder if they aren't Sodium Halide - which is a yellow, discontinuous spectrum that is very difficult for AWB to work with.

Where is this located? That is a lot of cool bikes.

I suspect you would enjoy Barber Motorsports in Birmingham Al too

ziggy53

amadeus wrote: »

yeah those are strange lights. they aren't flourescent and take awhile to turn on and make a hum while they do. but yes WB was auto.

pathfinder wrote: »

I wonder if they aren't Sodium Halide - which is a yellow, discontinuous spectrum that is very difficult for AWB to work with. ...

Either Sodium or Mecury-Vapor are difficult to impossible to color balance, but an audible hum means that they are likely 60hz, meaning that exposure is difficult too. You need pretty slow shutter speeds to gain a full wave and the cycling can throw off AF as well.

Use a long-ish exposure (1/30th is best but 1/60th might work), a tripod, either mirror lockup or live view (to help reduce camera shake) and manual exposure along with looking at the resulting histogram and "blinkies" to gauge if it's correct exposure. B+W processing will indeed eliminate the WB/color balance problem. Manually focus as well using Live View, if available.

Be careful about lens flare because of the lights in the background. Make sure that the lens and filter is clean and clear and that you employ appropriate lens hood and possibly flag extraneousness light as well.

Careful attention to details and obsessive methodology will yield the best results.

amadeus

so thanks to all who responded. I was at B&H and picked up a book on the D700 one of the Magic Lantern Series books.

It talks about lens's. It says the Nikkor AF type lens's do not communicate focus distance information to the camera. So my question is, since I've gotten the D700 I've wanted to use FX lens's not the DX 18-200 I was using with the D300. My son had some Nikon lens's from his film camera's and I've been using those. One of which is the Nikkor AF 28-80 lens. I've used it for action with some decent results. But how does it work on autofocus at all if it "doesn't communicate focus distance" to the camera?

ziggy53

amadeus wrote: »

so thanks to all who responded. I was at B&H and picked up a book on the D700 one of the Magic Lantern Series books.

It talks about lens's. It says the Nikkor AF type lens's do not communicate focus distance information to the camera. So my question is, since I've gotten the D700 I've wanted to use FX lens's not the DX 18-200 I was using with the D300. My son had some Nikon lens's from his film camera's and I've been using those. One of which is the Nikkor AF 28-80 lens. I've used it for action with some decent results. But how does it work on autofocus at all if it "doesn't communicate focus distance" to the camera?

Nikon has, I believe, 3 different AF mechanical technologies in use in their Nikkor lenses, and some of those lenses do indeed have the appropriate "chips" to create the distance data which can be recorded into the camera's metadata and recorded as part of the image file.

The primary reason for the distance information is for flash automation. In order for a flash to operate at its best in a straight-ahead orientation, Nikon's best flash automation, i-TTL, requires distance information in order to help set flash output accurately. Knowing the distance to the subject and calculating flash output to match is by far the most accurate method available.

Autofocus itself uses a type of digital "rangefinder" and there is a system inside most modern dSLRs that splits part of the image into 2 beams which are compared by special sensors (Line-type, Cross-type or Area-type) and the resulting data can tell the camera not only how far out-of-focus, but also the direction to focus (unlike contrast-detect autofocus which relies on "jogging" the AF system fore and aft until the best subject contrast is measured.)

The distance information is a byproduct of the AF operation, not necessary information for the AF process itself.

pathfinder

Auto focus really has nothing to do with the actual distance the subject is from the film plane. Auto Focus maximizes contrast in a local area, and once auto focus is achieved, then the distance to the subject is determined by some lenses. The information can be used for the electronic flash control in some camera-OEM flash systems.

Maybe a Nikonian can explain it better than I have, Amadeus. But the short answer, is that achieving autofocus does not require knowing the distance to the subject by the AF system.

Ziggy, you be me to it. Again!

Seneca

Shooting at 3.5 will give you a narrow DOF. Shoot somewhere around 5.6 - 8.0 and you'll get sharper images.

onesickpuppy

I'm really surprised that no one has offered a more correct solution............................so here goes

Yes...in the beginning you were starting with too large of an F stop (small number)....thus, you were getting a shallow depth of focus (from where ever your focus point was).
Yes...then you began to increase your F stop to larger numbers (more depth of focus)....but you allowed your shutter speed to decrease....causing soft images due to shake
Yes...while increasing DOF, you were hand holding so again....slower shutter speeds kept from razor sharp images

SO............what you should have done is................raised the ISO...........the D700 has super ISO performance!!!!!!!

You should have raised to what ever ISO speed needed to get a F8 or F11 AT a 200th of a second shutter speed!!!!!!!!! Then your images would have been SHARP......and larger DOF

Truly.......using a short focal length lens is a challenge especially if your subject isn't parallel to your camera body.

Question:??: in the shot of the garage filled with bikes.........what did you focus on??? hard to tell due to the "glare" but it appears to be the bike about 1/3rds into the shot

If you wanted all bikes sharp...try this.....single shot focus....small F stop (larger number)....focus on the nearest item in the view....keep finger on shutter button...recompose...snap shot

Now your focus point will start in the foreground....and due to the large depth of field of focus...all will be in focus

adbsgicom

I don't think you want to focus on the closest item unless that it your only focus. The DOF region is +/- the focal point, so if you want to maximize the stuff in focus go about 1/3 of the way in to the region you want. There is more focus behind the focal plane than before it. An oft-cited and handy little tool is here. There is an iPhone/iPod app for it as well.

amadeus

pathfinder wrote: »

You're right, the center bike is in focus, and the ones on either side are not in focus, just as I would expect at this close distance with a 50mm lens at f3.5 with a full frame camera.


Depth of field is a function of the distance from the image plane, the size of the optical sensor, and the aperture used, among other things.

You can read about depth of field on Wikipedia here - http://en.wikipedia.org/wiki/Depth_of_field

You can find a nice depth of field calculator here - http://www.dofmaster.com/dofjs.html There are DOF apps for the iPhone and the Droid as well.

I think your camera is fine, Amadeus. A full frame camera has a much shallower depth of field than a point and shoot. This can be an advantage, or a disadvantage depending on your needs and desires.

Step farther away, use a smaller aperture, use a smaller sensor based camera are all tricks to get more dof.

I have a question....

wouldn't depth of field change particulars or whatever you want to call it, on the same camera, vary from lens to lens given that lens are obviously different?

mstens

Yep, it'll vary. An ultra-wide angle will have a much larger DoF than a telephoto will. If you take a look at the bottom calculator link and play with it at various focal lengths you'll have a better idea of how much it'll vary.

pathfinder

Amadeus, I did not include lens focal length as a factor in dof, because it really is not a major factor, despite what folks will tell you, unless you vary the subject size.

If the subject size is held constant with different focal length lenses ( that is the subject is the exact same linear dimension on the sensor ) then there is almost no difference in dof with different focal lengths, as shown here - http://en.wikipedia.org/wiki/Depth_of_field#DOF_vs._focal_length

Read down to DOF versus focal length.

For those who prefer seeing this, instead of an optical formula, Michael Reichman demonstrated it nicely here - http://www.luminous-landscape.com/tutorials/dof2.shtml

mstens

I just had to go try this, and I have to say that you're right. DoF seems to be consistent as long as the subject size is identical. Why did I have to actually go try this? Because, to be honest, I've never shoved a wide angle tight enough into something to get effectively the same 'shot' as a medium telephoto (I just went and did this with some AI lenses, 28mm and 135mm to be specific, both at ƒ2.8). Part of the reason for selecting a different lens (at least from my point of view) is different compositional aspects.

Thanks for making me go play with something new!

pathfinder

Mike, I am glad you gave it a go. You can't imagine how often I have been flamed for saying that focal length is not really a major factor in dof. Folks just cannot believe it is true, but the difference is in the way we use wide and long lenses. (Also, whether a single focal length lens is wide or long, ultimately is determined by it's image circle, or the sensor sizel it is fitted to.)

I was first convinced of this by an article in Pop Photography many, many years ago, and was pleased to find Reichman's thread for use as a reference.

amadeus

thanks a lot pathfinder greatly appreciate it. outside of a laptop or phone or something with an app is there any product/gizmo I can get got for a DOF calculator?

heres one from yesterday that a few years ago I'd have called the greatest picture I ever took and now is just one that the focus was off. I'm getting some good ones though just need to get this DOF down wen I'm shooting.

thanks!

amadeus

and heres one from yesterday with better results.

pathfinder

I think both of those shots are dynamite, myself.

Most of the DOF calculators are either computer or Smart phone based. There is one for an iPod touch also. Or an iPad.

It sounds like you are wanting a dedicated hand held device? They used to make a hand held flat disc like a filght calculator I think, but I haven't sen one for years. Maybe Ziggy knows of one.

The funny thing is that our DSLRs have the calculating power to do DOF calcs with ease today, but no manufacturer seems to include that ability to my knowledge.

Older lenses had dof bands printed right on the lens barrels, but many no longer do that with the advent of AF.

mstens

I believe expoimaging makes DoF wheels. Other than theirs, which I stumbled upon online, I haven't seen one since college.

pathfinder

Mike nailed it!!


Expoimaging still offers an analog disc style of DOF calculator - the ExpoAperture2 DOF Guide - http://www.expoimaging.com/product-detail.php?cat_id=4&product_id=4&keywords=ExpoAperture2_Depth-of-Field_Guide