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Jewelry photography depth of field


#1

Tried unsuccessfully to post a photo of a piece of jewelry on the
Ganoksin gallery for non precious metal. My photo did not have
enough depth of field. Did anyone post a photo of their jewelry on
that gallery, would love to know what aperture was used on their
photo.

Thanks, Sigi
Sigi Eurich


#2

You need to use the smallest number on the dial. that is the closest
depth of field. 5.6 is close. f22 is far away. For all macro work
(and most photographing of jewelry falls into that) I turn off auto
focus so I can fine tune my image as to where I want sharpness (which
part of the piece).

HTH.
Betty H. Ott
Boop Photo and CopperWorks Jewelry


#3

Sigi,

Anytime you’re photographing anything in a close focus situation use
your highest available f stop (smallest aperture). There is a lot of
talk about how image quality degrades once you push a digital camera
past f/8. The smallest diameter aperture will give you a softer focus
than one in the f/5.6 - f/8 range but it also gives you the maximum
depth of field. It’s a trade off for which the smallest aperture wins
hands down. Even in non-close up work you have to enlarge by quite a
bit before the difference in image focus is detectable and even then,
in this modern age, you can fudge it pretty successfully with
software.

For jewelry documentation shots (ie. jury quality photos) crank the
lens to the smallest aperture, focus on what is most essential in the
piece if possible (a center stone for instance) or a center distance,
set your shutter speed accordingly and fire away. Officially you
should focus one third into the distance relevant to the closest and
further most points you want in focus (depth of field covers more
distance behind the focal plane than in front) but in close up
photography you’re dealing with such tiny distances that it is
irrelevant.

And once you make a shot, if your camera allows, magnify the image
on the camera’s screen to make sure what you want in focus is and, if
you still can’t get it all crisp, you can at least make a decision
about what’s most important. In general photography it is considered
more a more natural appearance if focus falls off into the distance
but the brain doesn’t like the foregrounds or leading edges of
objects to be fuzzy.

Here are a few other relevant facts if you’re interested:

Point and shoot cameras have great depth of field because thy use
such wide angle lenses. The close up feature uses the widest lens
angle which produces a greater depth of field than the telephoto end.
However, these cameras seldom go beyond f/8 in aperture while the so
called macro lenses used on DSLR’s usually go up to f/32 so it’s a
wash between the two on that score.

How close you position your item also, obviously, affects the depth
of field. The further away from the camera the greater the depth of
field will be. Also the smaller the item - and less detailed - it
will be so find the happy balance. But in practice erring on the side
of a little too far away is preferable to a little too close.

Use manual focus. At such tiny focus distances it is very difficult
to get an auto focus system to choose the point of focus that you
want it to. Many point and shoot cameras advertise a manual focus
feature but they are very cumbersome to use and results are mixed.
DSLR’s with a macro lens set on manual focus are far superior not to
mention much faster to use.

If your camera has a hot shoe (where a flash can attach) purchase a
strobe and a synch cord. This allows you to position the flash
directly above the piece with the unit connected to the camera via
the synch cord. If your camera features TTL flash sync then buy the
appropriate flash unit, set it on TTL, and you’re good to go. Very
simple lighting adjustments from there and all at the strobe, not the
camera. To use flash you need diffusion as the quality of unbuffered
flash is too harsh. You can buy frosted mylar at B&H PhotoVideo for
this or use a layer or two of brand new tracing paper. Build a foam
core board box (white) around the item with an opening for the camera
lens, cover with diffuser material, and use the strobe from above as
noted.

If your camera does not feature TTL then make sure the strobe you
get can be set to manual and with a couple of trial and error shots
you can quickly hone in on the correct exposure.

If using flash set your white balance to either auto or flash (try
them both) or do a custom white balance if that feature is offered on
your camera.

While tripods make everything really stable you can shoot handheld
pretty successfully if you’re using an off camera flash.

Do not use two different types of illumination in any shots (ever)
This includes turning off any room lights when doing your photo work.
Mixing light sources (and therefore color temperatures) creates color
inaccuracies that neither the camera’s systems nor software can
overcome.

If your camera offers histograms in the review mode always check
them before making a final shot. Even if you don’t see problems on
the monitor screen the histogram will show you if the exposure has
gone out of parameters. I prefer to underexpose just a little as you
get richer colors out of digital that way. However, don’t overdo it
as underexposure also increases noise in the image (mosaics of
colored spots in areas of darker value).

Don’t crank up the saturation in the camera. Leave it at normal.
Increasing saturation generally means moving colors toward their
relevant primary color. In other words it changes the actual color.
If you want to make any adjustments here your software is a better
bet.

Enough already,

Good luck,
Les Brown


#4

Generally, you need to use the smallest aperture the lens can
provide, and focus about 1/3 of the way into the piece, rather than
the closest surface. Some lenses are not designed for extreme
sharpness at their smallest aperture, that is why fixed focal length
macro lenses were designed. I use a Nikon DSLR, I have both the 60mm
and 105mm micro nikkor lenses. Their focal length is actually 50%
longer with the DX sized sensor in my camera body.


#5

One way to obtain good depth of field is to use a piece of software
like CombineZM. You take several images, each focussed at a slightly
different level of the object. The software puts them togather to
make one image that is sharp at all levels. I think it is a free
piece of software.

John


#6

There were some confusing statements in Saturday’s posts regarding
depth of field and my post was a definite offender. To clarify:

Simply put, aperture refers to the hole in the center of a leaved
diaphragm within the lens barrel, the diameter of which expands and
contracts per the camera’s auto controls or the users manual settings
allowing light to pass through, in varying amounts, creating the
image on the sensor or film.

Big diameter lets in lots of light, small diameter lets in much less
light. Specific diameters have specific numerical designations called
f/numbers for instance f/3.5, f/8, etc. These numbers are the result
of computations but the really important things to know about them
are the following:

  1. The larger the actual aperture the smaller the aperture f/
    number. The f/value, usually printed on the lens or camera body,
    refers to the greatest possible diameter for that lens. This largest
    of apertures will usually fall between f/1.4 and f/5.6 depending on
    lens. The smallest possible diameter available to a lens (again,
    product dependent) will usually be f/16, f/22, or f/32. Some point
    and shoots don’t go even this high.

  2. The smaller the actual aperture (and the larger the f/number) the
    greater the depth of field the lens is capable of. So to get the
    greatest depth of field set your lens to the largest f/number it
    offers, such as f/16, f/22, or f/32.

  3. This will, in order to get a proper exposure, force the shutter
    speed to slow down if you’re using available light or studio
    lighting. If you have to slow the shutter speed below 1/8" you are
    risking increased noise (digital only) in the image as well as
    potential focus problems from camera shake. Tripod mandatory.

  4. Using off camera flash allows (or should if the flash unit is
    powerful enough) you to use the highest flash synch speed the camera
    offers - usually somewhere between 1/125" and 1/500" regardless of
    f/number setting. Handheld possible.

Sorry for any confusion my previous post may have caused - and for
the typos as well.

Les Brown


#7

Hi Les,

If I may, with respect, I’d like to correct a couple of your
statements for the benefit of budding photographers out there. I’ve
been paid for my photos for over 40 years now, and teach,
specifically, jewelry pghotography. And there’s been a lot of
disseminated here which is not correct or, at best,
confusing.

The reason point and shoot cameras offer increased depth of filed
compared to most DSLR’s is because of their smaller sensor size (crop
factor relative to focal length). It has nothing to tt do with
whether the lens is wide angle, normal or telephoto.

If pictures taken from the same subject distance are given the same
enlargement, both final images will have the same DOF, REGARDLESS of
lens focal length. The statement that wide angle lenses produce
greater depth of field is a common misconception, oft-repeated, but
it is simply inaccurate.

Shooting at minimal aperture WILL degrade the image because of
diffraction and it is visible in even small images. I’d suggest not
going below F/16 and judicious use of the the Unsharp Mask tool
combined with the High Pass filter method to get what appears to be
maximum depth of field while retaining edge sharpness without
producing artifacts in the image. Glad to place a tutorial here if
someone can tell me how to get images to be seen on this forum.

The best recommendation we might make is for the photographer to
shoot in RAW mode, which gives us much greater latitude to break the
normal rules and gives us far wider leeway in
post-processing…simply put, better images.

Wayne Emery
thelittlecameras.com


#8

I recently started getting great depth of field using a Canon EOS
450D/Rebel XSi camera and DSLR Remote Pro software (I use it on my
Windows PC – the software is also available for Macs, and for
working with other Canon cameras). The software is available at

http://www.ganoksin.com/gnkurl/up

The software takes multiple images, each at a different focus. I
combine the images using a technique called focus stacking
(explained at

http://www.ganoksin.com/gnkurl/uq

– there is commercial/paid software, which I haven’t tested, to
stack the images, but I use the free CombineZM software suggested on
this page).

The results are great.
Dan Kamman


#9

Mr. Emery & Orchid Table Top Photography Community,

In my previous posts on this thread I made the following statements:

Point and shoot cameras have great depth of field because thy use
such wide angle lenses. 

This is only true if comparing two differing focal lengths from the
same subject to camera distance. If you move the longer lens back to
accomodate an identical field of view for both lenses DOP (depth of
field) will be more or less the same. While Mr. Emery has the
relationship between DOP and camera position reversed he is correct
that both wide and long lenses can achieve the same amount of DOP.

The close up feature (in point & shoot cameras) uses the widest
lens angle which produces a greater depth of field than the
telephoto end. 

Same correction as above. And since one would, of course, adjust the
subject to camera distance for identical framing this was pretty much
a non sequitur. Apologies.

The smaller the actual aperture (and the larger the f/number) the
greater the depth of field the lens is capable of. So to get the
greatest depth of field set your lens to the largest f/number it
offers, such as f/16, f/22, or f/32.

Mr. Emery has taken me to task on the above in terms of resulting
image quality. He is correct that diffraction (the bending and
blurring of the incoming light rays that pass within a certain
distance of the physical aperture) creates a softer image through a
lens set at its smallest aperture than at mid-range. And his
assertion that you will get a substantially poorer image at the
smallest aperture may be true for cameras with very short focal
lengths such as all point & shoots have. It is not a problem for the
the DSLR style cameras.

Here’s why: An f/32 aperture in a 100mm lens (such as you would use
on a DSLR) has an opening with an area of roughly 5.0 sq mm. A
similar aperture on a 4.3mm lens (which is the focal length at the
wide end of the Nikon Coolpix P300) would have an area of approx 0.21
sq mm. While the amount of diffraction will change with the area it
does not change proportionally and actually increases in distortion
as the aperture diameter decreases. While no point & shoots have an
f/32, whatever the smallest aperture is could possibly create
unacceptable image qualilty. In fact, on the P300 mentioned above the
widest aperture of the lens (at the wide end) has a square millimeter
area of only 4.17 - smaller than the 100mm lens at full stop down.
And likewise, the reason you get a sharper image at f/16 as opposed
to f/32 (in a given lens) is that the F/16 aperture is so much
larger than the F/32 reducing the effects of diffraction.

Despite that, if you’re using a DSLR style camera with a "macro"
lens in the 50mm to 105mm range, I stand by my statement to use the
smallest possible aperture for any close up work of three dimensional
subjects. Again, check out the photos on my website. The great
majority were taken at F/32 on a Nikon D40. Yes, if I blow the images
up to 100% on my computer I can see a subtle loss in sharpness. By
the time I’ve sharpened them in software they are quite acceptable.
More acceptable than similar photos at wider apertures in which much
of the subject fore and aft of the focus point will be truly out of
focus. If I want very large images- poster size say - I use software
which gives me the larger image with, again, acceptable sharpness for
the viewing distance of such a large photo.

For those of you using point & shoot cameras I’d say do a few tests
and find out where the acceptable range is between blurriness fore
and aft of the focus point and unacceptablly soft images overall.

Finally, in reference to Mr. Emery’s statement that

The reason point and shoot cameras offer increased depth of field
compared to most DSLR's is because of their smaller sensor size 

he is incorrect. An image focused on a film/sensor plane will exhibit
the same depth of field regardless of the size of that film/sensor
plane. What changes, however, is the apparent magnifying power of the
lens when compared to the traditional 35mm format.

Often point & shoot focal lengths are given in “equivalent” figures
to full frame 35mm lenses - the current benchmark standard.
Consequently the Nikon P300 is marketed as having a focal length
range of 24mm - 100mm when in fact the actual focal lengths range
from 4.3mm to 17.9mm. The size of image, at 4.3mm say, in relation to
the sensor size of the P300, however, mimics the same ratio in image
size to format that one achieve in using a 24mm lens on 35mm film.

For people not wishing an education in optical science but wanting
to take the best possible photos of their work I would recommend the
short and concise explanation of depth of field found about half down
on this webpage:

http://www.ganoksin.com/gnkurl/uz

Sorry for all the distraction from jewelry discussions,
Les Brown


#10

Thanks to every body’s help with photography, will certainly try it
all out and wish me luck! Thanks to Betty H. Ott, Leslie Brown, Rick
Hamilton! Sigi