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Old Sep 23, 2009, 10:20 AM   #11
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Sarah-

You started an excellent thread.

You might also want to add a couple of more things.

Like..
And one of the things I've never understood is why a fast lens is so much more expensive than a slower lens. What is that keeps a lens from being able to have a wider aperture in the first place that would justify increasing the price by whole number multiples? And why can't a zoom lens normally support the same max aperture across its zoom range?
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Old Sep 23, 2009, 10:48 AM   #12
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The speed of the lens is dependent on the glass and the design with the glass being the big coust.
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Old Sep 23, 2009, 11:11 AM   #13
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A Fast Lens has a large pupil diameter in relation to its focal length. For instance, a 100mm lens with a 50mm pupil diameter is an f/2.0 lens, while the same lens with a 25mm pupil diameter is an f/4.0 lens. Lenses with larger pupil diameters (apertures) require larger lens elements. Larger lens elements mean greater chance of imperfections, so they require tighter controls on quality to be even as good as a smaller aperture lens. So a large aperture lens is more expensive to make than a small aperture lens, and a good large aperture lens is a lot more expensive to make than a good small aperture lens.

And lenses with variable focal lengths (zoom lenses) have more elements and more moving parts, which makes them more difficult to make, and much more difficult to make well. Add a large aperture to that, and you're talking about a lot of money.
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Old Sep 23, 2009, 11:35 AM   #14
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Sarah-

You started an excellent thread.

You might also want to add a couple of more things.

Like..

1). Why are prime lenses superior to zoom lenses?

2). What does macro exactly mean (1:2, 1:1 etc...)?

3). Why are 100m (35m eq.) (+/-) lenses perfect for portrait?

4). What specific range do you need for your primary regular purpose?


- Hiro
1) Fixed focal length lenses are easier to design (fewer elements, and fewer moving elements) and therefore at a given price point are usually optically superior. However the computer-aided-design era zoom lens can be incredibly good, in fact superior to many of the older fixed focal length designs.

2) Macro is simply a measure of how large the projected image is when compared to the subject. So 1:1 means that a 10mm object in the world throws a 10mm image on the sensor. A 1:2 ratio means that a 10mm object in the world throws a 5mm image on the sensor. For many "macro" purposes a 1:4 ratio is actually sufficient. e.g. flowers. But clearly a bee is much smaller than a flower so for a bee you would prefer a 1:1 ratio. There are even very specialized macro lenses that have a better than 1:1 ratio. Macro lenses in general are VERY sharp, but are much slower to focus because their gearing is different.

3) That is just a matter of taste. A lot of people like the mid-telephoto range for head or head-and-shoulders portraits. The slight flattening is somewhat flattering. It is also easy to make these lenses very sharp. It is also easy to get good background blur. Hence they are commonly used for portraits. However that is not to say that you cannot take portraits with both much wider or much longer lenses. I personally find portraits with the mid-telephoto length lenses to be very boring and uniform. I think most of the best portraits I have seen are taken with much wider focal lengths. 50mm-e, 35mm-e or even 28mm-e.

4) This is very much a matter of taste. But the most commonly needed range to cover is 28mm-e (medium wide angle) to about 70mm-e (short telephoto). Often lens manufacturers will try to extend this a bit at the wide end to around 24mm-e and at the long end up to 130mm-e.

Just about all kit lenses cover the 28mm-e to 70mm-e range. Novices should be careful to take the crop factor into account. "Old" lenses that were designed to cover this on film cameras. So a 28-80 on a crop frame camera would give an equivalent view to a 45-130mm which is a poor choice for most people.

Individuals vary however. I shoot just about everything with a fixed focal length 50mm-e lens and seldom use zooms.
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Old Sep 23, 2009, 12:19 PM   #15
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peripatetic-

Thanks for your excellent explanation! I have always appreciated your unbiased opinions.

- Hiro
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Old Sep 23, 2009, 1:34 PM   #16
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A Fast Lens has a large pupil diameter in relation to its focal length. For instance, a 100mm lens with a 50mm pupil diameter is an f/2.0 lens, while the same lens with a 25mm pupil diameter is an f/4.0 lens. Lenses with larger pupil diameters (apertures) require larger lens elements. Larger lens elements mean greater chance of imperfections, so they require tighter controls on quality to be even as good as a smaller aperture lens. So a large aperture lens is more expensive to make than a small aperture lens, and a good large aperture lens is a lot more expensive to make than a good small aperture lens.

And lenses with variable focal lengths (zoom lenses) have more elements and more moving parts, which makes them more difficult to make, and much more difficult to make well. Add a large aperture to that, and you're talking about a lot of money.
Thanks, TCav. This is very helpful. But you fail to appreciate the depth of my ignorance. When I see an 18-200mm Sigma lens with apertures of 3.5 to 6.3, and apply what I think I have learned from your comments, it appears that the Sigma should be a much brighter lens than 3.5 at the wide end. The marble is still not falling in the hole for me.
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Old Sep 23, 2009, 1:53 PM   #17
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Many, many thanks to all who have contributed to this new thread-

Your participation is greatly appreciated. My original post was an "initial stab" and attempting to provide some basic information that I thought might be helpful to anyone considering a DSLR camera.

Please keep in mind that I am an engineer by training, and have taught for many years. Certainly others on this fine forum are more technically precise and more adept than I am. So, I see this as a joint or community effort, where all of us can share our expertise. Thanks for joining in on this thread.

Here is my installment #2 that I wrote last night:

Hi there, Folks-

A question that we hear quite often is this: Will a DSLR camera really improve my photos, considering I am moving from a Point & Shoot camera to a DSLR camera?

Generally speaking, there is a real and somewhat measurable possibility that you will see a real improvement in your photo, because now you have a much better tool set available to you.

However, another factor can also come into play when you attempt to judge the improvement in your photos. Hand in hand, with the improved tool set provided by a DSLR camera, is the person behind that camera. In other words, your photo experience and proficiency will also come into play when judging the actual improvement in your photos.

I am very used to always using my current camera’s LCD screen to frame my photos, is that facility available on DSLR cameras?

That feature on a DSLR camera is called: Live View. It is not always available on the least expensive entry level cameras because it take a modification of the basic optical system within any DSLR camera. Most professional reviewers and experienced DSLR camera users acknowledge that among the DSLR camera manufacturers, Sony seems to have the very best Live View implementation. Live View can be found on the Sony A-330 camera and above, including the soon to be introduced A-500 series of cameras. However, the entry level, Sony DSLR camera, the A-230 DSLR camera does not include the Live View option. The Sony A-230 camera is currently the lowest priced, entry level DSLR camera, if you a looking for a two lens kit option.

I am not long and strong on photo experience, I generally shoot with my camera set to the fully automatic mode. Is that feature available on DSLR cameras?

Yes, all of the entry level DSLR cameras feature a fully automatic mode of operation, as well as a variety of Scene Modes. However, to honestly get the greatest value from your DSLR investment, you should plan to gradually make the transition from using the fully automatic mode to at least using the “P” mode, which is an abbreviation for the Programmed Auto Mode which operates very much like the fully automatic mode, but allow the photographer to make small changes as required by the ever changing photo environment the photographer is shooting within when taking photos.

What is the easiest way to improve my photo skills and techniques?

Because we are now in September, the start of the fall semester at most Community Colleges, or if that seems too quick for you, perhaps in January, when the winter quarter begins, is an excellent time to find out what digital camera courses are being offered at a near-by Community College.

That would be the easiest and quickest way to improve your photo skills. Read the course description carefully. Ideally, you will learn the most if the course being offered has both lectures and hands-on shooting sessions. When both types of instruction are offered, then generally speaking more functional learning takes place. Some folks, can learn easily from just lectures that are presented with good PowerPoint assisted visual aids. However, some persons learn better by actually taking photos, due to the fact that they are used to “hands-on” training.

I teach several digital camera courses for our local Community College, and I make it a point to include lots of audio-visual instruction, coupled with regularly scheduled hands-on shooting sessions.

Do all DSLR camera lenses work on all DSLR cameras?

No, unfortunately each camera manufacturer use a proprietary lens mount that is different from the lens mounts used by other camera manufacturers. So when considering a DSLR camera, you should understand right up front, that essentially you are buying into a camera system.

Spend adequate time making a good decision about which camera manufacturer’s DSLR system jives with both your current and future DSLR camera expectations. Why you might ask? Because changing systems at a later date could be an expensive proposition. That change in systems could require a change of all your lenses, and perhaps even your external flash. So your system decision is a very important one.

I definitely want to go to the DSLR camera level, but I face some very real budget constraints. What is the most inexpensive DSLR camera that I should consider?

If your budget is currently a constraining factor, you might really focus on two brand names. Both Sony and Pentax brand DSLR cameras are able to use “legacy lenses.” What that means is simply this: Sony cameras are able to use all of the older Minolta and Konica-Minolta auto focus lenses with type A lens mounts. The same is true for Pentax brand and third party lens maker’s auto focus lenses (such as Tamron and Sigma, who made lenses for the current mounts of both Sony and Pentax DSLR cameras in the past.

Lenses for a DSLR camera are a sizable investment. While camera bodies constantly change and are upgraded, lenses retain their value and are a way in which you can save money by looking at the used market. Reputable and dependable used lens markets are found at the following websites:

www.keh.com
www.bhphotovideo.com
www.adorama.com

And for those among us who might have a greater appetite for increased risk, there is also the market offered by www.ebay.com.

Even if you later decide to upgrade your camera body to a newer or more well featured camera body, you will, generally speaking, sell the old camera body you are upgrading from, and move to the new and improved camera body, keeping your favorite lenses to use on your new camera body. That is why that “system decision” is so very important to you.

For example, when I purchased my Sony brand DSLR camera, I wanted more flexibility than the stock Sony brand kit lens offered. That Sony kit lens was a Sony 18-55 mm lens, which in actual use, and in 35mm terms, equated to a 28 mm to 84 mm lens. As my walk around lens, I wanted more zoom flexibility. So I purchased a used Sigma brand 18 mm to 125 mm lens for around $(US) 140.00. Because I was using the lens on a Sony brand DSLR camera that features “in camera body” image stabilization, the fact that the lens I purchase did not have stabilization really did not matter at all. Any lens mounted on a newer Sony brand, Pentax brand, or Olympus brand DSLR camera that all have “in camera body” image stabilization. Therefore you save some real money because any lens mounted on a DSLR camera with “in body” image stabilization automatically has full image stabilization. Had I owned a Canon or Nikon brand DSLR camera and wanted to have image stabilization, I would have had to purchase the newer Sigma 18 mm to 125 mm lens with image stabilization built into the lens. Sigma calls that feature OS, and the cost of a new version of the very same lens equipped with image stabilization, would have cost $(US) 399.00. That is a huge difference in price than the $(US) 146.00 that I paid for as used Sigma 18 mm to 125 mm lens in the Sony “A” mount.

That fact is NOT true for Canon and Nikon brand DSLR cameras. Both Canon and Nikon made the decision to NOT offer an “in camera body” image stabilization system. Image stabilization, for Canon and Nikon brand cameras is only incorporated in their lenses. And as you might expect, IS equipped lenses are more expensive than non IS equipped lenses.

Which camera brand of DSLR camera has the best image quality?

All of the DSLR cameras produced by Pentax, Sony, Nikon and Canon produce excellent image quality. You really cannot make a bad or poor decision. So your brand decision should be motivated much more by your system decision rather that an image quality decision.

Well once again I have attempted to give you a lot of information, but this post has become quite long. So we will stop here for today. Please don’t hesitate to ask any specific questions that you might desire. This is a community thread and we want to make it as useful as possible to all readers.

Have a great day.

Sarah Joyce

Last edited by mtclimber; Sep 23, 2009 at 1:57 PM.
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Old Sep 23, 2009, 3:20 PM   #18
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Great topic and good thread. I just wanted to clear up a few points in Sarah's last post:
I am very used to always using my current camera’s LCD screen to frame my photos, is that facility available on DSLR cameras?
I would add that while liveview is available on many cameras, in many instances it's a poor way to frame photos because it's less stable. Even the smallest DSLRs are heavy compared to most pocket digicams. Holding the camera at arms length to compose shots can lead to poor results because it's tough to hold steady. For example, when I use a digicam I use the screen but on my DSLR (which has live view) I use the optical viewfinder because it's simply steadier.

I definitely want to go to the DSLR camera level, but I face some very real budget constraints. What is the most inexpensive DSLR camera that I should consider?

Sarah spoke about Pentax and Sony using older lenses. Be aware these lenses aren't manufactured any more. So you can't buy them new - you MUST buy them used. In many cases such lenses are only manual focus and in others manual aperture as well. And, manual focus can be more difficult on many DSLRs because of smaller viewfinders and less magnification compared to film SLRs. They also don't usually come with focus screens designed for manual focus. Although those can be purchased separately. So, used older lenses CAN be a great budget option if you are OK with the constraints I mentioned. It's also worth mentioning that you can buy used lenses in ANY system to help control costs. So if you look at Nikon used lenses - while you might not find 30 year-old lenses on the market you'll still find quite a bit of 2 year old lenses.

On image stabization:
Sarah mentioned in-body vs. in-lens. But her comments about IS lenses in Canon or Nikon costing more isn't necessarily true. Many consumer grade lenses in both camps have IS built in and these lenses sell for competitive prices vs. Sony/Oly/Pentax. And, in fact, you also need to consider other lens costs - especially as you move up the chain. As an example, you can buy a Canon 70-200 2.8 (non-IS) for $1200. The sony model is about $1800 I believe. So, if IS isn't necessary that's a big savings. If you want the IS version, it's a shade less cost than the Sony. So, in general, the notion that lenses are cheaper in systems other than Canon / Nikon and IS lenses in those companies cost more than their counterparts due is not always true. The one area where there really is a system benefit for in-body stabilization is short prime lenses - typically Nikon and Canon don't offer IS in their 135mm or less primes. So, if you use those types of primes and IS is important to you then Oly / Pentax / Sony have a decided edge.

What is the easiest way to improve my photo skills and techniques?

Sarah mentions community colleges. This can, indeed, be a good idea. Realize though that the hiring criteria there is a bit different than a university. Just because someone is teaching a class in digical cameras doesn't mean they're proficient with regards to photography. One concept simply teaches you how to operate a tool, the other teaches you how to create with a tool. A perfect example is a guy at Home Depot - he can teach you how to use a table saw but may or may not know how to actually build anything. Also, if you're jumping into DSLRs I advise you to look for PHOTOGRAPHY courses, not 'digital camera' courses. For the reasons mentioned above - you want to learn photography, not how to access menu options. You want the emphasis on the course to be on photography and not helping everyone figure out how their digicam operates and where a feature is baried in the menu structure.

Additional avenues: Books. Books are great because you can take them into the field. Photography hasn't changed a lot since film - the tools have changed in that there are more bells and whistles. But, getting better photos is usually about understanding photography. If you learn photography you can spend 1/2 hour with a manual to learn how to operate the tool.

Also, this forum and others are WONDERFUL resources of knowledge. You can ask specific questions and get multiple answers back. You can also find genre-specific experts. For example if you have a question about issues with some macro shots you're taking - you don't necessarily need someone who owns your camera. What really helps is getting advice from people that shoot macro. Remember, most issues are photography related and the answers are often independent of the camera. In my experience when you ask self-proclaimed photography experts questions they'll give an answer even if they have no hands-on experience to answer you. That's why it can be tough getting answers from an instructor. Their ego can get in the way of sending you to another resource so they'll make up an answer they THINK is right. With the internet and photography forums you can find people that shoot just about anything. You may find wildlife advice from a Nikon shooter on one site and portrait advice from an Oly shooter on a different site. Without doubt, these people who actually DO the type of photography are the ones who helped me the most.

Anyway, just some other things to consider.
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Old Sep 23, 2009, 6:03 PM   #19
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Thanks for an excellent post, JohnG-

There are multiple sources for increasing and improving your photo knowledge and photo techniques. BTW, JohnG, I also has taught for the Universities of Oregon and California.

Have a great day.

Sarah Joyce
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Old Sep 23, 2009, 7:01 PM   #20
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BTW, JohnG, I also has taught for the Universities of Oregon and California.

Have a great day.

Sarah Joyce
Hey that's great. Did you teach photography courses there?
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