Trying to learn to fly my shiny new Pentax DSLR camera, and the comment about the space shuttle is not far off the mark!
Do any of you use tha vast range of ISO speeds available, and if so, what rule of thumb works best?
With my old film camera I would stick in a roll of Kodachrome 64 and get after it, but this thing wants to complicate the proceedure by offering up a huge range of speeds!
May you be in heaven half an hour before the devil know`s you`re dead!
ISO is all about light sensitivity and with film-based cameras it was a function of the film you used and could not be changed by the camera; your Kodachrome 64 would have had a fixed ISO (or ASA) rating. In the digital world, you can treat each picture as you want and it would be the equivalent of changing your film for each shot. Since getting the optimal exposure is about getting the right amount (not too much or too little) of light onto the sensor, you can now adjust the shutter speed, the aperture setting and the ISO setting to achieve this.
So, if it's bright sunlight and you are taking a landscape shot where you want a small depth-of-field and set a small aperture (f22 for example) at a shutter speed of around 500/sec you might have your ISO set to around 800. In a similar situation where you want to take a portrait of someone in the foreground and have the background out of focus with a large depth-of-field you will want to have your lens almost wide open (f2 or lower if your lens supports it) but there will be significantly more light so you will either have to ramp-up your shutter speed or you can reduce the ISO setting.
You can see how this triad of options can come into play for low-light or fast action photography and the best advice is to go out there and play - the great thing about digital photography being there is almost no limit to the number of shots you can take! The rate limiting steps to the quality of your shots will be the speed of your lens, which is why fast lenses (sub f2) are more expensive, and the size or quality of your sensor. Top end, full-frame cameras can get up to ISO settings of 25,000 and while it will be grainy, it's pretty good if you want to take shots of a break-dancer in a darkened night club with no flash!
"A man who does not think for himself, does not think at all." Wilde
There is a lot of confusion around depth of field and depth of focus, etc. and maybe I've got the terminology wrong. If you want a blurry background and lots of 'bokeh', open the aperture (a low f-stop number), if you want foreground and background in focus then close it down (a high f-stop number).
These are sometimes called 'shallow' and 'deep' focus respectively...as I understand; it can be confusing.
"A man who does not think for himself, does not think at all." Wilde
Just out of curiosity, I did a bit of very amateur photography back in the eighties with film SLR's and understood ( I hope,) how the various parameters were derived, ISO is a chemical property of the film, F stop was the opening of the aperture behind the lens and shutter speed was provided by varying the width of a slot that swept the surface of the film when the shutter was released.
Now in a digital SLR, is there any similarity in any of the above or is everything just digital manipulation of what the sensor sees all the time?
The processor now does the same thing digitally, the triangle of ISO/Aperture/Shutter speed are the only things you really need to adjust. Messing with white balance, exposure compensation, and all those fancy presets can all be done with photoshop.
A good cheap lens for great low light imagery and bokeh would be a prime 35 or 50mm, F1.4 or 1.8.
Who is the happier man, he who has braved the storm of life and lived or he who has stayed securely on shore and merely existed? - Hunter S Thompson
With a digital camera for the novice, is there an actual difference between ISO and shutter speed? They both seem to influence the same thing although I admit that I don't really know much about the subject. I was just thinking that now virtually everyone uses digital, it's perhaps time to have a method of controlling them more directly related to what is actually happening and not related to how a film camera worked.
Yes, when using a DSLR adjusting the shutter speed gives you control over set time intervals so you can choose how long it stays open for. When adjusting the ISO the camera will decide how long to leave it open for to get optimum lighting using the ISO setting you have chosen.
Who is the happier man, he who has braved the storm of life and lived or he who has stayed securely on shore and merely existed? - Hunter S Thompson
OK, thank you for your answers. I was just thinking that for the younger novice who has probably never seen a roll of film, some of the terminology might be a bit confusing.
My camera calls ISO "sensitivity", but uses the same scale as film cameras. The other functions are still the same. It is the same as giving you the choice of what film speed you would use, except that you can choose the "film speed" for each shot, or leave it on auto for the camera to decide, taking into account other factors. It also provides for a much larger range of ISO settings that were never possible with film cameras. But it is just one of a multitude of settings that you can control that were just not available with film cameras.
May you be in heaven half an hour before the devil know`s you`re dead!
Actually I've just been reading that a modern DSLR still has a mechanical shutter which surprised me as I thought it was done digitally and that explains why you still need an ISO/sensitivity setting.
I would like to get back into photography but unfortunately I've reached that glorious stage of being a middle-aged breadwinner where despite working hard and making loads of money, due to dependents, homes, school fees, etc. buying an expensive camera comes way below the dogs vets bills on the budget sheet!
I now use a mirror less camera which due to it's nature is silent which is great for candid street photography shots and the like.
My Fujifilm X100 has been superseded (X100s) and as a result the price has dropped from around £1000 to around £350 (what I paid). The only downside is that the auto focus can be a bit slow to react sometimes, but for the money saved I can live with that.
It's also quite small so can be carried easily.
Here is mine. Note - the grip, thumb rest and lens hood are added extras.
That's a real beauty, Randy! I have a Panasonic Lumix mirrorless camera and although it takes great shots, you really have to be careful to make sure the focus is spot-on. It will often end-up being out enough to notice when you view it full size on your computer whilst being OK on the viewing screen.
For those who don't know what a mirrorless camera is, it's a recent hybrid between an SLR and a compact but more towards the SLR side. An SLR allows the user to see the image the right way up through the viewfinder because it takes the image from the lens and reflects it through a mirror and 'pentaprism' (posh mirror) into the viewfinder, very much like a periscope. The mirror is roughly the same size as the film/sensor plane and set at 45 degrees. This takes up quite a bit of space and is largely what causes SLRs to be bulky; the mirror box. When you take a photo, the mirror flips up and exposes the film/sensor plane to the image from the lens, exposing your photo. This also results in the classic shutter 'click' sound as the mirror moves up and down again. In a mirrorless camera, such as the Olympus PEN, Panasonic Lumix etc., the sensor is similar in size and characteristics to an SLR but the image is relayed not to a viewfinder but a digital screen, like a compact camera, and this does away with the mirror box, allowing the camera to be quite a bit smaller. Some mirrorless cameras are really rather good but you're always one step removed from the real world image and rapid response of the 'Mark 1 Eyeball', which can be a problem in fast response scenarios.
Clearing-up ISO (famous last words on the forum!), think of it as a digital 'gain' device. ISO is a real world measure, it's a genuine logarithmic scale that represents a calculable amplification of the sensitivity of your sensor. Just like cranking-up the gain on an audio amplifier, you will make the signal louder but you will also introduce unwanted noise because there's no such thing as a free lunch in this world. The trick is to be able to increase the sensitivity enough to get away with the aperture and shutter settings you want (without physically changing the available light) whilst not introducing too much noise that is noticeable or undesirable in the finished article.
"A man who does not think for himself, does not think at all." Wilde
