STILL CAMERA TIPS: Terms Discussion

[gdjsky01]

In the spirit of the gallery here that the moderator has worked so hard to organize, I prefaced this post with Camera Tips... as opposed to VIDEO Tips or something else....

Terms

Shutter Speed. The faster the shutter speed the more likely you are to 'stop motion' or 'freeze' the image. This is a good thing if you want a clear image of your rocket. Of course if you want a blurred effect then that is a different story. Lower speeds let in more light, higher speeds let in less light. So 1/250th of a second is seems fast, but 1/1250th or better is desired for freezing a rocket in flight.

Aperture Almost all cameras have a variable opening in the lens or in the light path. There are subtleties I won't get in to, but for now. The bigger the opening the more light gets in. Smaller the opening the less light gets it. A side effect is the bigger the opening the smaller the range where things are in focus. This is known as Depth of Field. Aperture looks like f/2, f/4, f/5.6, f/8, f/10, f/13 etc... larger numbers equal smaller openings which means less light, more depth of field (more range of stuff in focus). Also with zoom lens so prevalent, high apertures tend to take sharper pictures, lower apertures not as much. Lens are a compromise. The less compromise, the higher the cost. Most consumer lens/cameras are at their best at f/5.6 and above.

ISO Back in the old days film chemistry was altered to make certain films more sensitive to light in varying degrees. So ISO 100 film was not as sensitive to light as ISO 400. So if you were shooting in low light, ISO 400 was preferable as it was more sensitive (I am being simplistic here). The trade off was ISO 100 gave better looking photos than ISO 400. In modern digital cameras the terminology is the same AND the result is the same. All that is different is we are turning up the gain (amplification) on the digital chip instead of changing the chemistry. We still have the trade off on image quality (to varying degrees depending on $$$$ spent). High ISO has more digital noise than lower ISOs. (chip size and makeup play a role here as well - but lets leave that out)

Focal Length
For now, and for simplicity sake, lets just say focal length is what you are changing when you zoom in or out (if your camera has a lens that moves - internally or externally). Not digital zoom. That is something else. I am referring to moving optical components in the lens. Generally the more you zoom, the high the Aperture number goes (unless you spend $$$$), so the less light you get, the more shake you get, and the narrower the area the lens covers (called Field of View). Nothing wrong with zoom, you just need to balance it with everything else.


For rocketry I try and MAKE the camera optimize a high shutter speed and small aperture. That way I freeze the motion (high shutter speed) and maximize the amount of range that is in focus (higher aperture). Obviously to do that I need a lot of light. Normally getting enough light is not an issue as it's daylight. If the amount of light IS an issue, I try to raise the ISO rather than open up the aperture. That way I keep my fast shutter, wide range of in focus area in return for somewhat worse image quality (noise).

How we MAKE the camera do that is a subject for another post....

Comments?? Thoughts? Additions?

One last item... you can mitigate a lot of what I said were 'trade-offs' by buying high end DSLR cameras and high end lenses. But you still have to know WHAT to do with them.

[jadebox]

For rocketry I try and MAKE the camera optimize a high shutter speed and small aperture. That way I freeze the motion (high shutter speed) and maximize the amount of range that is in focus (higher aperture). Obviously to do that I need a lot of light. Normally getting enough light is not an issue as it's daylight. If the amount of light IS an issue, I try to raise the ISO rather than open up the aperture. That way I keep my fast shutter, wide range of in focus area in return for somewhat worse image quality (noise).

How we MAKE the camera do that is a subject for another post....

At the risk of jumping the gun .... :-)

One way to get your camera to use a fast shutter speed and small aperture is to set it to "Sports" mode (assuming it has a "Sports" mode). This mode usually also selects continuous focus and a drive mode allowing the camera to take a burst of "continuous" images when you hold down the shutter.

-- Roger

[Aksrockets]

Tips for actually keeping the camera on the rocket:
Zoom out unless you are experienced. I see lots of people zoomed way to far in and the rocket never makes it in the frame.
USE THE VIEW FINDER this makes a HUGE difference in the quality of the footage
Know the speed of the rocket. (does the rocket look small and have a big motor?) Have a mental video of what the flight might look like before the rocket launches.
Be smooth: Use one slow, arching motion to follow the rocket, lots of people jerk the camera around to much, trying to center it on the rocket.
It's not good to film a rocket with a tripod, I find you need more control over the camera.

It's also interesting to have different angles. Personally, I like the 3 cam set up: Pad cam, onboard and ground cam that tracks the rocket.

Editing:
Unless it's a rather unusual rocket, don't include pad set up. It might be important to YOU but no one wants to see more then like 10 seconds of pad set up. I find myself skimming over the pad set up completely.
If you use music, don't include it for the boosting stage in the flight, If the music overpowers the sound of the motor, it ruins the effect (IMHO). Save the music for the recovery.
I like to use a picture of the rocket instead of a pad set up.
Clearly label what motor is used.
Slow motions are cool but they shouldn't last forever. Try to shorten slow motion time to only the interesting parts of the flight.
Typically, My ideal video for one flight is from 30sec-1:30sec.

All of this being said, I break my own rules quite a lot.

All of these are my own personal tips accumulated from a few years of filming club launches.

Alex

[luke strawwalker]

I'd throw out there that the bigger the lens, the more light you gather... and usually, the higher the quality of the image you'll get. You'd probably be in a better position to explain the effects of quality lenses than I am. I DO know that a good prosumer cam will produce better pics than a point-n-shoot merely due to the fact that the prosumer models will have a lens about 2 inches in diameter or thereabouts, versus about maybe a half-inch in diameter on a point-n-shoot. Of course the DSLR's that use larger, high quality lenses are better still, but they have prices to match of course...

Digital zoom is, IMHO, ABSOLUTELY WORTHLESS... it's a "cheat" that digital camera mfg's used to get around the fact that they used pretty cheap and limited lenses on the early digital cams to keep the prices down enough to sell lots of cameras... digital zoom actually just 'zooms in' on part of the chip, in effect, capturing the light falling on that part of the chip and "magnifying it" to fill the entire picture size displayed... digital camera chips are usually quite a bit smaller than even a 35mm negative (a lot are about the size of a 110 negative, or even smaller) and this means that when you start 'shaving off' the edges to create a 'digital zoom' you're not using the entire surface area of the already "small" chip area, which cuts into resolution... and of course, like regular optical zoom (zoom lenses) the more you zoom in, the harder it is to keep the subject framed in the pic and the harder it is to avoid shaking, blurring, and keep everything in focus. If you have "digital zoom" on your camera, turn it off and leave it off for best quality...

Megapixels... the old adage was "more is always better" but now this isn't so true anymore... back in the 2-3 megapixel camera days, yeah you could get MUCH better pics out of a 4 or 5 megapixel camera, and better yet out of an 8 megapixel camera. BUT, we've reached the point where a 12 megapixel camera is NOT going to produce that much better of a picture than an 8 or 10 megapixel camera... unless you're taking pix that you then blow up into billboard size, where you NEED the extra resolution of very high-megapixel cameras to avoid graininess in the massively blown-up image (in the old days, this related to negative size... which is why Ansel Adams photos look SO good at poster size, despite being taken on "ancient" cameras, than more 'modern' pix taken using more 'modern' 35mm cams... the old film was 3-4 times the size of a 35mm film frame (the negatives were 3-4 times larger than a 35mm negative). For most rocket applications, I've found 5 mp to be plenty... and I set my camera's megapixel setting down from 10 megapixels to 5... it makes smaller filesizes (about 1 MB or so) versus the larger filesize at 10 MP resolution, and hence faster to write to the card and faster turnaround between pics. My cam's burst mode shoots 33 frames in about 1.3 seconds, at 3MP. This fills up the buffer and then it takes about 15-30 seconds to write those 33 pix to the card.

Just a few observations that I'll throw out there... not an expert in the field and I'm certainly open to correction...

Later! OL JR

[fyrwrxz]

Sincere thanks for all this info. You guys know i never post pics because I'm camera (and many other things) illiterate. I'll try some of this stuff now and maybe venture into Area 51 for a trial run. Just simple tricks tips and mods-I haven't the patience to do a build thread and bless those that do. I promise to keep the pics of my feet, thumbs and pet rock to a minimum. Once I figure out how to turn it on.....

[gdjsky01]

I'd throw out there that the bigger the lens, the more light you gather... and usually, the higher the quality of the image you'll get. You'd probably be in a better position to explain the effects of quality lenses than I am. I DO know that a good prosumer cam will produce better pics than a point-n-shoot merely due to the fact that the prosumer models will have a lens about 2 inches in diameter or thereabouts, versus about maybe a half-inch in diameter on a point-n-shoot. Of course the DSLR's that use larger, high quality lenses are better still, but they have prices to match of course...

Lens quality usually shows itself in the extremes. It also, as I mentioned, shows itself in less compromises. All cameras that have non-interchangable zoom lenses are a compromise. No exceptions. Indeed all zoom lenses are a compromise. Its just a matter of how much of a compromise. (ie $$$$) Normally the compromises are at the extremes. The very short (wide) zoom settings and the very long (narrow) zoom settings. Holy grails are Apochromat (APO - aka chromatic abberation free - no color fringing) lenses that can zoom yet keep a constant aperture. For example my zoon lens is a compromise. It zooms from 35mm (.6x) to 125mm (2.5x) but at 35mm it can open up to f/2.8. However at 125mm it can only open up to f/5.6. An expensive zoom might be able to keep a constant f/2.8 and be sharp no matter what the zoom! Of course for the privilege you'll pay up to $2500USD. Big color free glass equals big money. I am an amateur astronomer. Astronomy and fine optics go together. I know exactly what a 3 inch diameter f/6 APO telescope costs. Want to go to an even lower (wider) aperture? F/4 can run you $4000 or more. But you can do just fine with FAR more modest lenses!!!! Just increase the f/ number to f/8 or more to sharpen them up. Don't think you can't do well with your point and shoot... we just have to play with the settings.

Digital zoom is, IMHO, ABSOLUTELY WORTHLESS... it's a "cheat" that digital camera mfg's used to get around the fact that they used pretty cheap and limited lenses on the early digital cams to keep the prices down enough to sell lots of cameras... digital zoom actually just 'zooms in' on part of the chip, in effect, capturing the light falling on that part of the chip and "magnifying it" to fill the entire picture size displayed... digital camera chips are usually quite a bit smaller than even a 35mm negative (a lot are about the size of a 110 negative, or even smaller) and this means that when you start 'shaving off' the edges to create a 'digital zoom' you're not using the entire surface area of the already "small" chip area, which cuts into resolution... and of course, like regular optical zoom (zoom lenses) the more you zoom in, the harder it is to keep the subject framed in the pic and the harder it is to avoid shaking, blurring, and keep everything in focus. If you have "digital zoom" on your camera, turn it off and leave it off for best quality...

All true! Normally you can 'disable' the digital zoom in the menu. But it's not required because if you are zoomed in far enough to kick the camera into the digital zoom range, which normally picks up after the mechanical/optical zoom, you are 'probably' zoomed too far in for launch. Chip size is simple. The smaller the chip (95% of all digital cameras are very small) the higher the digital (quantum actually) noise. Most consumer cameras are small chips with WAY too many pixels. You 'need' (IMO) 3 to 8 megapixels max. But its' hard to find them because camera makers found out people are dumb and think more is better. If you have the $$$$ by all means buy a camera with a large sensor (chip). Like a Canon 1D or 5D... or Nikon equivalent.

Megapixels... the old adage was "more is always better" but now this isn't so true anymore...

It's just not true at all. More pixels on small chips mean more digital noise. It's not worth it.

My cam's burst mode shoots 33 frames in about 1.3 seconds, at 3MP. This fills up the buffer and then it takes about 15-30 seconds to write those 33 pix to the card.

Bingo. Burst mode (continuous shooting) is one of the things you are looking for in a still camera for a rocket launch. My Canon 40D is 5 or 6 frames per second at full rez shooting RAW images. Casio has some high speed cameras that have video and still modes that are very speedy.


Good stuff JR!

[dr wogz]

Filters:

All lenses should have a filter. The main reason is to protect the actual lens glass & its special coating. It’s easier to clean & replace a filter than a lens!

The most common filters are ‘Skylight’ & ‘UV’ filters. We photographers put them on, and leave them on. We will swap them out for others, when needed.

UV & Skylight filters reduce the amount of ‘blue’ that can come thru on outdoor shoots. Most won’t notice the slight reduction of the blue cast in outdoor photography. But then again, with Photoshop & such, the blue can be altered to suit the shot.

Again, mainly to protect the lens glass itself. They come in a wide range of sizes. I’ve seen some ‘point & shoot’ cameras with threading to allow the addition of a lens filter.

Circular Polarizer filter: This is probably the next most common filter in a photographer’s kit bag. Add it can help ‘punch up’ colors & will reduces glare & reflections. Reflections off water, or off a window front.. You can get some pretty dramatic sky & clouds with one. The outer ring rotates, so you can align the polarizer to match the light waves.

There are a myriad of other filter types, some artistic, some limit certain color wavelengths.. But anybody starting out should have at minimum a UV or skylight on each lens..

[jadebox]

We're getting away from discussing "terms." Of course, I was the one that started the digression. But, I'd suggest starting separate topics on things like general tips, filters, etc.

-- Roger

[BABAR]

Ultimate Black Background for Pictures.
Since many rockets are thought of as "Space Ships", a black background tends to set some rockets off pretty well. Here are some shots of a scratch built heavily modified clone of the Estes EPM-010. By going outside at night, using the flash, with the background so far away the flash doesn't illuminate it, you get pretty close to a perfectly back contrasting background.

[Marc_G]

Cool. I like the eagles!

[gdjsky01]

you get pretty close to a perfectly back contrasting background.

Excellent tip!


One issue as you can see is most camera flashes are terribly weak and fade quickly. Of course if that effect looks good, then its a keeper. If you need more light you can use a contrasting single background color of any sort like a sheet, or poster board, or even a cloudless sky. Then you can select that color and cut it or change in. Assuming you have an image editor that allows that.

Or remove the background and insert a new layer with the background you want. Again it assumes you can and dont mind the effort.