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Old Feb 12, 2008, 6:11 PM   #1
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As I said I'm completely new. I'm your generic Joe consumer in most aspects. I'm good with computers and know how to use photoshop etc. However when it's come to cameras I usually just looked at my price range and found the one with the highest MP. Things are about to change though!

I'm an airline pilot. I've seen too many magnificant things to not be taking photo's of them. From flying over downtown New York on a crisp night to landing through a snowy storm in Cleveland I've had some mental pictures taken I wish I could share with others.

Since I'm looking around at new cameras to get, can't decide on DSLR or a Canon G9, I'm seeing a few things I don't understand.

--Ok so I want to know more about the differences between DSLR and something like the G9 or any other point and shoot. I understand what a SLR is so I'm wanting to know a little more in debth. Lets talk lens size. What makes the SLR so much more effective? I have an older 35mm Minolta that has taken great pictures from a trip in africa. I decided to pull the lens out to look at the size and on the side it says it goes up to 300mm. Is that the same as someone saying "this camera has 7x optical zoom"? What does the 25mm-300mm really mean? I see some places say 35mm equivalent of 210mm etc.

For instance the G9 says "6x optical 35-210mm f/2.8-4.8 zoom, 4x digital zoom". My minolta 35mm has a lense that goes to somewhere around 250mm. Does this mean that the G9 can zoom almost just as much yet is half the size? I guess I don't see the connection. Why the huge lense on the SLR when something smaller can get higher magnification? The Sony Cybershot is 10x magnification with a 38-380mm (35mm) equivalent lens and would take up considerably less space than a DSLR with my 300mm lens. Where's the payoff for DSLR?

The reason I'm so concerned is because, as stated, I see a lot of beautiful shots. I had a small point & shoot camera that doesn't take very good shots of another aircraft passing in the distance. While the MP of the camera are high, 7.1, the aircraft always seems like little spec that I can barely see. Is this because the size of the lens is as small as my little finger?

I'm sorry to sound like such a brain dead idiot. This is just a world that I don't understand and I want to make sure that when I make the purchase it's for the right reasons. Basically I'm sticking with just a couple choices for now. The Canon powershot G9 or the Sony A350. If I had a lens in the A350 that was 35-210mm equivalent
just like the zoom on the G9 where would the advantage be to go with the DSLR (Megapixels aside)?

As you can see I'm pretty varied. Maybe after learning a little more I'll be able to give a better idea. I'm looking at picking one up in April.

****EDIT****

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Old Feb 12, 2008, 7:10 PM   #2
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The difference in lens sizes is just the facts of optics. DSLR sensors are bigger and further away from their lenses as compared to Point and Shoot cameras. The payoff for DSLRs is image quality (bigger sensor=less noise), lens speed (you can gte lenses that let in more light that those on a Point and Shoot - faster shutters, lower ISO), higher optical quality (most P&S cameras' lenses are too ambitious and have many optical compromises).
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Old Feb 12, 2008, 8:25 PM   #3
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Duck,

You asked some very good questions, which in order to answer fully is beyond the scope and size of this forum. The following explanation is intentionally elementary, hopefully not to the point of providing erroneous information.

A 35mm film camera is called that because that is the size of the film it uses - 35mm. Digital cameras don't use film - they have sensors. The sensors have light gathering devices called photo receptors imbedded on them which receive the light entering the camera through the lens and convert it to electrical impulses. A typical point and shoot (P&S) digicam has a sensor that is very small when compared to a 35mm film. Most P&S cameras today, have 1/2.5" sensors
You can see a comparison of sensor size here, as compared to 35mm film.:


http://en.wikipedia.org/wiki/Image:SensorSizes.png


Notice the size of the 1/2.5" sensor (typical P&S) compared to the APS size (typical DSLR). Huge difference, right? Even the 1/1.7" sensor of the G9 is small in comparison. The manufacturer can use a much smaller lens to focus light on a small sensor. The larger sensor requires a much larger lens. In order to produce a zoom lens for a DSRL with the same zoom range of a megazoom P&S, would probably result in a lens so large and heavy that you wouldn't be able to carry it. In addition, imagine taking the same 10 million photo receptors from an APS sensor and trying to fit them on a 1/2.5" sensor. The only way to do that is to make the receptors smaller. Smaller receptors have less light gathering ability, which produces more noise in low light situations.

Regarding focal lengths of lenses, most P&S camera manufacturers identify the 35mm equivalent, e.g., a 6 to 67mm lens on a P&S is the equivalent of 28 to 300 mm on a 35mm camera. The DSLR manufactures provide actual focal lengths. However, there is a ‘crop' factor involved, based on sensor size, which results in an equivalent focal length which is 1.5, 1.6 or 2 times the stated focal length, e.g., an 18 to 200 mm lens, with a 1.5x crop factor has an equivalent focal length of 27 to 300mm.

What does this mean to you? I think, if you go the DSLR route, you would need two lenses, to cover wide angle to telephoto situations. The DSLR system (with top quality lenses) will cost you more money. You could cover the entire range with one lens if you go with a P&S megazoom (but with reduced quality). There are advantages and disadvantages to both systems.

How much do you want to spend - $500? $10,000? How important is image quality to you? Is size and weight a consideration? How much reach do you need? Is 400mm enough? Need 600mm? I don't think the G9 would have enough reach for your needs. You need to set goals and restrictions, then go to a camera store and handle different types. Ideally, borrow a couple of cameras from friends for one flight and experiment.

Then, good luck.

The Hun

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Old Feb 13, 2008, 12:24 AM   #4
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Excellent post! Extremely well written. My hat goes off to you. You've done an amazing job at explaining and things are much more clear. As far as how far I need to look I couldn't tell you. The only digital camera I have is the Sony Cyber-shot which I thought was 7.1mp but after pulling it out realized it is 8.1pm with 3x zoom. Price right now I'd like to keep around $1k. I don't know anything about lenses I just know the two that I have on my current Minolta. A key reason I've decided to look into the A350 from Sony. I need to find more info on the lenses but I think mine will work. I'm currently trying to find lenses for sale on sony's website but have come up dry.

Imagine shots of this type.

http://www.airliners.net/open.file?i...&photo_nr=

I'm also planning on taking a few trips to other countries, have to abuse the travel benefits!!! I figure I'll save the pictures on a HD and one day when I get enough I'll have them printed into poster size and decorate my home with them.

Thank you for your great explanation. I couldn't have asked for better!
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Old Feb 13, 2008, 5:44 AM   #5
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Your minolta lenses should work on a Sony camera. These are film lenses and not optimized for digital. You may (or may not) have issues with purple fringing or contrast/color rendition. I would still recommend getting whatever kit lens comes with the camera, as they are typically great values. Another issue you may have, is with the crop factor of DSLR's (1.5 for sony cameras), your lenses will appera have a narrower field of view. An 28-70 lens will have the field of view of a 42-105. This is great is you shoot on the telephoto end, but not so good if you like wide angles. Still, using your film lenses is a great way to jumpstart your lens collection.

You should be able to find plenty of Minolta lenses on the used market. Sony is still new to the DSLR game, and doesn't have a ton of lenses available, epsecially on the used market. Many of their lenses are on the pricey side as well. Their lens assortment will grow over time as they become a larger player in this market.
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Old Feb 13, 2008, 8:58 AM   #6
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ToiletDuck wrote:
Quote:
I don't know anything about lenses I just know the two that I have on my current Minolta. A key reason I've decided to look into the A350 from Sony. I need to find more info on the lenses but I think mine will work
Are they Minolta Autofocus Lenses? Any Minolta Autofocus (a.k.a., Minolta A-Mount, Maxxum, Dynax, Alpha) lens will work on a Sony DSLR, and they'd also be stabilized.

What lenses do you have now?

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Old Feb 13, 2008, 11:27 AM   #7
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I'm at an airport at the moment. I won't be home till later. However they are autofocus lens. I have not problem purchasing my lens however if I go that rout then I have no reason to ony be faithful to Sony.
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Old Feb 13, 2008, 11:35 AM   #8
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I keep up with most Minolta AF lenses, since I shoot with a Konica Minolta Maxxum 5D and Sony DSLR-A700. I've got a couple of Minolta Maxxum film bodies, too. So, post some specifics about your lenses and I'll let you know what I think. They may or may not be worth taking into consideration when buying a new camera model.

These are lenses I have for use on a Konica Minolta Maxxum 5D and Sony Alpha 700 (a.k.a., DSLR-A700): Minolta 28mm f/2, 50mm f/1.7, 100mm f/2, 135mm f/2.8, 24-85mm f/3.5-4.5, 35-70mm f/4 Macro; Konica Minolta 18-70mm f/3.5-5.6; Tamron 20-40mm f/2.7-3.5, Tamron 35-105mm f/2.8; Vivitar 70-210mm f/2.8-4. All Autofocus (and all are stabilized on a Konica Minolta or Sony DSLR model).

The only "made for digital" lens in the bunch is the 18-70mm f/3.5-5.6, and it rarely gets used since my Tamron and Minolta zooms designed for film cameras outperform it from an Image Quality perspective.

More often than not, you'll find me using a Minolta 24-85mm f/3.5-4.5. It's my favorite walk around lens. I've got some images taken with one using a Konica Minolta Maxxum 5D in this thread (note that they're straight from the camera, so they'd sharpen):

http://forums.steves-digicams.com/forums/view_topic.php?id=94653

You can pick up one of these lenses in excellent condition for about $100 - $150 if you shop around (look at keh.com for examples), and it's a very decent lens from my perspective, giving me roughly the same angle of view I'd get using a 36-127mm lens on a 35mm camera model, within a stop of most of the brighter 24-70mm or 28-75mm f/2.8 zoom models in a smaller and lighter lens (and brighter than most consumer grade lenses with it's focal range).

You can find an MTF chart for it at photodo (and keep in mind that you don't use the entire image circle so ignore the last part of a chart on the right away from center if you're using an APS-C sensor). IOW, you get the "sweet spot" of most lenses designed for film on this type of camera.

For example, the Minolta 24-85mm f/3.5-4.5 AF lens grades at a 3.5 on their tests (which is not bad for a zoom lens with it's focal range, especially one selling for as little as you can buy one for). It's also graded higher than similar lenses in Canon or Nikon mounts. So, you can find some great bargains with high quality optics in used Minolta zooms.

http://old.photodo.com/prod/lens/minolta.shtml
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Old Feb 13, 2008, 3:00 PM   #9
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Excellent info. As I said I'm not against purchasing my own lens. I like how you touched on focal lengths etc. Can you point me to a good Q&A where I might be able to read about them more? I'd like to know what I'm actually looking rather than just a price tag and a mm perspective.
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Old Feb 13, 2008, 11:40 PM   #10
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Before jumping on the DSLR bandwagon, you might want to give some thought to how much kit you want to be carrying around with you. Presumably, you will be spending quite a bit of time away from home and living out of suitcases. A DSLR with a couple spare lenses, batteries, and other necessities, is going to add considerable bulk and a bit of weight to what you'll be carrying around. If you can live with this, a DSLR will definitely give you the best image quality and flexibility. Swapping lenses while you are supposed to be flying the plane is not one of the great ideas of modern man, though. :!:

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