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Techno-Photo-Nerd Boring Stuff


kbobam
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Hi! I'm so glad you're here!

The topic title was designed to keep our friends who aren't particularly interested in this stuff

from wasting their time. So I'm going to assume you're at least a little interested.

Honestly, I don't think you'll be disappointed. I'm about to reveal what may be one of the least-known

technical approaches to achieving razor-sharp high quality photos under certain conditions.

I'm sorry this has absolutely nothing to do with marbles. It's kind of the exact opposite. I'm talking

about what I'll call 'infinity focus'. This is basically where your camera is focused when you're taking

a photo of a distant landscape. Or the stars at night. It's the 'far end' of your camera's focusing ability.

Here's the deal. Optical designers put 'leeway' into their lenses for several very good reasons.

This actually allows them to focus beyond infinity (what a concept!) in most situations.

You don't want this to happen at any given moment, although it's a terrific thing that it theoretically can.

I'll just mention one reason for this, which is that the same camera might have a different

'perfect far-away focus' in the Arctic than it would have on the beach in Maui.

Thermal expansion/contraction, don'tcha know!

The good news is that many modern cameras handle this situation quite well with the auto-focus you

probably use most or all of the time. But if you're a perfectionist and enjoy experimenting, you really

owe it to yourself to try some 'manual focus' adjustments. You might be thrilled with the results.

Below is a photo I recently posted of the 'light trail' of an airplane flying through the night sky.

I took this one allowing the camera to tell me where 'infinity focus' is. Below that is another photo

of pretty much the same thing I took a few days later. With this one, I spent the extra time to

precisely 'tune' the manual focus to infinity by actually looking at the screen and judging the best

focus by 'eye'. Photos here at TMC aren't reproduced perfectly, but hopefully you can see that the

second shot had a much better 'technical' outcome.

I'm going to shut-up now, since I'm talking too much and it's late and I'm tired.

Will add a few quick details to this technique later for those interested.

In the meantime, if you're not sure whether your camera can focus manually, check the

(appropriately named) manual under "manual focus". Many of us aren't aware that our cameras

can do this, because truth be told, it hardly ever comes up.

And you know what? It just hit me that we can apply a similar approach to our close-up photos

of marbles! So we'll talk about that too. Oh boy! :lol:

P.S. I've noticed that sometimes my fairly large-sized photo files don't appear quickly, if at all,

here. 'Refreshing' the page seems to fix this.

_DSC1225_zps76jyzsab.jpg

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Hi, Ann!

I was actually just this second thinking of you.

Was in the middle of a second message here, when TMC

cleverly informed me that someone had just posted to this topic.

(I've always thought that's a particularly neat feature

of the way the message-board format used here works.)

Before I clicked the 'show me' button, I saved what I was writing,

so let me 'paste' it here, and add the last few lines to it. ( :

I'd also like to ask our friends who are knowledgeable concerning 'heavenly bodies' about something I noticed here.

In the second photo there's a point of light pretty much in the middle, and a little bit above the line of the plane's flight.

If you're looking at TMC 'full screen' on an average sized desktop monitor, I'd say it's about an inch above it.

Okay! Here's the question. This star-like thing is a distinct point of light. Actual (I'm assuming) stars in the photo

are showing as short 'lines' because of the long camera exposure and our rotation relative to them. This is most

clearly seen in the brighter one toward the right. The mystery body also has a reddish color tinge to it.

What's going on? Could it be a satellite that's moving in lock-step with us?

Or are we also 'in-synch' with other planets? I'm embarrassed to say that it never occurred

to me before to wonder about this sort of thing and I'm woefully ignorant. :blush:

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I see what you're talking about -- I see a few more, too -- but none have a reddish color tinge on my monitor. It could easily be a star, a planet, or a satellite. Somewhere there's a site (of course there is) where you can look up satellites by time and location (well, maybe not all satellites), so maybe you could confirm or eliminate satellite by going to work on that . . . but it makes me tired just thinking about it.

There are times when I can live with uncertainty.

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Sounds like a more than reasonable approach to me!

Let's see. I think I can add the last bits of the focusing technique experiment now.

Take a photo of the night sky or those distant mountains in the usual auto-focus way.

Now switch over to manual focus. At this point you'll be focusing in one of several ways.

If you have a traditional lens with a genuine focusing-ring you'll be using that. Otherwise

you'll probably be using 'up and down' push-buttons, or an awkward 'control wheel' like me.

Regardless of the method, you'll now be involved with doing a slowly shrinking back-and-forth

motion until you're pretty sure you have the focus just right. It's easiest to do with something

small and bright, so stars at night are a good example. If you're shooting something on

terra firma during the day, a bright reflection in the distance is also good. These bright spots

make the focusing easier because adjusting the focus back and forth will make the spot look

bigger either way you go. What you want is to make the spot appear as small as possible.

(The 'spot' doesn't even have to actually be in the photo you're taking. It's just for establishing

the camera setting. Feel free to take distant shots in a completely different direction!)

So having done that, take another shot and take a close look at both of them on your

computer later. If they look identical, terrific! No worries! But if your manually-focused

shot is better, it's nice to know that you have this option.

Talking too much again. Some things never change.

Will add the last part about manual focus and marble

photography in the near-future for those who can stand it! ( :

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The photos posted are pretty clearly long time-exposures done at night and not hand-held.

So I'm not sure why you're asking this question or to whom it's directed. :dunno:

You are right, I just read your text about focussing properties and did not think about the photos enough.

[...]

I'd also like to ask our friends who are knowledgeable concerning 'heavenly bodies' about something I noticed here.

In the second photo there's a point of light pretty much in the middle, and a little bit above the line of the plane's flight.

If you're looking at TMC 'full screen' on an average sized desktop monitor, I'd say it's about an inch above it.

Okay! Here's the question. This star-like thing is a distinct point of light. Actual (I'm assuming) stars in the photo

are showing as short 'lines' because of the long camera exposure and our rotation relative to them. This is most

clearly seen in the brighter one toward the right. The mystery body also has a reddish color tinge to it.

What's going on? Could it be a satellite that's moving in lock-step with us?

Or are we also 'in-synch' with other planets? [...]

Since your long-exposure and firm mount has the camery in-synch to earth rotation all stars (galaxies and so on)

get sweept to parallel lines - or parallel segments of a circle to be more precise. I assume you took the photo far away from northpole so I conclude that this reddish spot is not a star. But I have no idea what it could be beside satellites on geo-stationary orbit (the camera thus should have pointed to the same direction your satellite dish does) or some artefacts of the image sensor chip? For a planet to be 'in-synch' there are way too much of those reddish looking spots around so I want to rule out this theory.

BTW: I need to zoom in the picture to notice this mentioned spot at all.

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The 'mentioned spot' is definitely a little elusive depending upon one's viewing conditions.

I was kind of amused at one point to realize that staying away from 'ambient light' (in this

case, turning off my desk lamp) and looking slightly to the side made it much easier to

locate on my computer monitor. Just like you'd do in the wild, looking up at the sky! :lol:

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I feel reasonably sure that this spot isn't an artifact.

But it could be, and I'm really glad you brought up that concept!

Anyone who has any interest in experimenting with longer than normal

exposure times needs to know that modern digital cameras do sometimes

create 'dots' like this, or other little blobs of color that aren't actually there,

when using these long exposure times.

There might be a 'setting' on many people's camera that addresses this issue.

On my camera it's called "Long Exposure Noise Reduction".

This name is very misleading! It has absolutely no connection with any of

the other 'noise-reduction' settings you may have.

If you can identify what your particular camera 'names' this setting, there

really isn't any reason you shouldn't have it set to 'on'. It won't have any

effect at all on the normal photos you take most of the time.

Personally, I have all the other noise-reduction settings turned 'off'. They

definitely have a noticeable effect on your normal photos.

Whether you want this effect is a matter of personal taste in terms of how

you want your photo to look. But basically, using any noise-reduction other

than the one for this special-situation is a case of intentionally blurring

your photos in an effort to avoid any 'grainy' look. Your photos will look 'smooth',

but they won't be as razor-sharp as they could be. Not worth it in my opinion. ( :

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Going to talk about marbles now!

And I'm going to skip all the diagrams and theory and explanations!

(But you have to let me have this one slightly overdone advertising statement just for the fun of it.)

What I'm going to tell you is :banana006:The ONE BIG SECRET TECHNIQUE that world-famous marble

photographers DON'T WANT YOU TO KNOW ABOUT! :banana006:

Here is why you might find it worthwhile to try some close-up marble photos using manual focus:

The best shots are going to be when you're focused right on the point of where the marble is closest to you.

Reflections of the lights you're using are likely to fool your camera's auto-focus into focusing on them, and

they're not going to be on the closest part of the marble.

Try aiming a laser-pointer on that closest point, and fine-tune your manual focus on that. That's it! See ya! ( :

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