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06-22-2011, 01:19 AM   #1
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N00b . . . kr. lens. and books

Hi all

I've not really been into photography but it is something that I would like to take up as a hobby.
I'm particularly impressed by the white kr because I am shallow and it looks nice lol.
I also like that the reviews I've read have indicated it's more a mid range slr for entry level prices.
So standard comes with I think an 18-55 mm lens
what does that mean lol
I want something that is quite versatile, something that I will be able to use at pretty close range, but with the option of maybe doing some scenery outside.
I am really unsure about where I'm going and I've read that I should just get the stock lens and as I use it more, buy a next lens depending on where in the range i use it.
The thing is for an extra 100-150 bucks you can get a twin set with a 55-300mm lens which seems to me is a better deal, and you can shoot more in it.

obviously I need to find a bit more about photography before I purchase, can anyone recommend a good book for starters

Also can someone explain to me what the differences in lens means. I've been ignoring the letters and numbers after. . . . like DA and f.3.5 because I figure they don't matter too much for me . . . . but if I buy the wrong ones initially I imagine life is gonna be a little more expensive for me after the fact?

Anyway long winded. Any help anyone?

06-22-2011, 01:43 AM   #2
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Being new myself, I can tell you what I did, which was read a lot of reviews, decided I wanted a Canon, went to the shop and bought a Pentax!

I think you need to go to a camera shop and actually try the camera out. Personally I thought the colour ones looked a little tacky - but that's just me ( a camera should be black, dammit!). All the reviews pointed to a Canon, but when I held it I felt it was low on build quality - now I know that is probably wrong, but it's what I thought. The Pentax felt much sturdier and I liked the layout of buttons and just how it felt in my hands.

This forum is an excellent place to get advice, so I will leave the more technical aspects to those who know better, but essentially the lens tell you how far it will focus. So the 300mm lens is capable of focussing further away than the 55mm. Feel free to correct me if I'm wrong!

Hope this helps and welcome to the forum.

Last edited by joshfishkins; 06-22-2011 at 01:44 AM. Reason: Really should proof read before pressing post
06-22-2011, 05:14 AM   #3
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I did my research and bought the Pentax K-r, two lens kit. I'm extremely happy with it. It takes good pictures, and allows me to shoot in "auto" mode, and to play with the various settings, to include totally manual (that's interesting and I've deleted a LOT of photos doing that). There is a book called "Understanding Exposure" that I just bought and it's helping me quite a bit. Good luck.
06-22-2011, 06:05 AM   #4
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I am a novice at this, but I here is a link that gives a good graphic explanation of what you are asking.

Focal Length and Aperture Explained for the Photography Novice | Digital Photography Tutorials

I just bought my KX used, and it didn't come with the kit lens. After doing a lot of reading, I opted to buy aTamron AF 18-200mm lens at Amazon for $240 AR. This is a good all around lens that can be used for items close up and far away also without having to change lenses.

If you have the kit 18-55mm lens, having the 55-300mm lens would allow you to zoom in on objects that are farther away.

06-22-2011, 06:36 AM   #5
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The twin kit lenses (18-55 & 55-300) are considered to be better than average in image quality compared to other manufacturers and are a good value. All of my images in the PPG (Pentax Photo Gallery) and PEG (Pentax Forum Exclusive Gallery) were taken with my kit lenses, DA18-55 & DA 50-200 (The DA55-300 is now considered better than my DA 50-200). I have used these lenses since 2005 and I am very pleased with there performance.

As for a learning site to start with, here is a camera simulator that will help you get a feel for the relationship between ISO, Shutter Speed, and Aperture.

The SimCam: Film and Digital Camera Simulator - Photonhead.com

Tim
06-22-2011, 06:46 AM   #6
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Welcome aboard.

Good for you doing some research before buying. If you can get the addition of the 55-300 for $150, grab it.

What I wanted to address briefly is the number, f3.5 etc. When it comes to the lens and the photos you can make with it, that is probably the most important specification. What it refers to is the speed of the lens. More simply put, the amount of light the lens will pass through to the sensor. The smaller that number the faster the lens and the more expensive.

Lenses like the kit zooms (the lenses you are considering) are variable speed for lack of a better term. The 18-55 for instance is an f3.5 - f5.6. What that means is as you zoom the lens from 18 to 55, the exposure requirements will change. Zoom lenses that this does not happen with are said to be constant aperture (the f number) lenses. When you learn about exposure you will understand why this may be important to you. The more expensive zooms will be of this type in most cases (they are also larger in size and weight).

As to my suggestion of what to read about, Exposure. Exposure and the 3 factors that affect it. Shutter speed (the amount of time light is recorded), The Aperture (f number, the amount of light allowed to pass through the lens to the sensor/film), and the ISO (the Sensitivity to light, you may also see it referred to as ASA). Each of those also affects the Type of photo you can make but their importance takes a passenger seat to knowing what they actually do with respect to one another.

At the end of the day, it doesn't matter which camera you buy. They all take photos and if you understand what makes a photo (exposure), the rest will come with practice. It also doesn't matter what format you read about. Film or digital. Exposure requirements and their effects haven't changed since the beginning of photographic time. All that has changed is how we record it.

Good luck..

06-22-2011, 07:33 AM   #7
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It is great to start somewhere and this forum is a brilliant start =) Which ever lens you consider, there is also the 'lens reviews' above which you can check out, also you can look at flickr streams as well and see what type of photography and images they are getting out of there lenses and camera.

When I was reading up about buying my K-x, one thing that I read somewhere was not to get the kit lens which comes with the camera because if you don't get the pictures you want, it will make you frustrated and most likely you will put down the camera and walk away thus wasting your money. That is why I splurged a bit more and got a Sigma 17-70mm which performed brilliantly (now selling it as I invested in primes -> lenses that are fixed focal length and fixed aperture which is normally faster than zoom lenses e.g. Pentax FA 35mm f2.0)

To start with, if you have a simple point and shoot, alot of them have the option to adjust some simple functions like shutter speed iso etc. You should also play around with that (my sister's p&s also has aperture control as well which is a great start) And try to get your hands on a Kr to see what it feels like. The camera body could be too small, too big, you might not like button layout etc. And if you like the white K-r, go for it! No one will think you are crazy, if anything they will be intrigued by your unique camera, but in the end its not the camera, but the photographer behind it which makes the artwork.

Also, there are alot of books but the most important book I found that helped me was the instruction manual that came with my K-x. Try see if you can download a copy from the pentax site or something. After that, play around with your camera in Av (aperture priority) or Tv (shutter priority) mode

Also for a site that explains all the different terms in front of the lens e.g. DA, FA, F etc check this out Pentax K-Mount Lenses Explained: The differences between various Pentax lens series
06-22-2011, 08:47 AM   #8
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Welcome aboard, Marc.

First, I would recommend you buy the two lens kit, not from practical experience of me buying it. But based on my practical experience with similar lenses. For outdoor sports, the 55-200 will be a workhorse.

Second, check out this link on the explanation of various pentax lenses:

Pentax K-Mount Lenses Explained: The differences between various Pentax lens series

And here's a good link that discusses the exposure triangle (aperture, ISO, shutter speed):

Understanding the Exposure Triangle | 101

Third, buy ANYTHING written by Bryan Peterson. He's a genius and he writes decently well. I have his book Understanding Exposure, and it's fantastic. Great for beginners to learn the basic concepts, and great for advanced shutterbugs to remember and refine those concepts.

I think that will get you started; it's a lot of info, but it's very good info.

06-22-2011, 12:48 PM   #9
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Welcome to the SLR world.

I suggest you pick up a cheap book related to the subject. As it will explain the basics. Nothing too advanced. It will go along way in explaining what you need and why you need it.

The two lens kit is a very good deal for the price. 18-55 and the 55-300. The 50-200 is okay but is getting a bit dated. Those numbers are the focal lengths of the lens. Pretty much the zoom factor. 18 being wide and 55 for things farther away. 300 is very far away. If you ever played with a P&S camera they also have focal lengths written on the barrel. However the numbers are much smaller due to sensor size and other factors.

Information such as DA L 18-55mm F3.5-5.6. This is where the details are DA is Pentax designation for digital lens built for digital cameras. "L" is designation for value model. Meaning is doesn't have the bells and whistles such as weather resistant or quickshift technology. F3.5-5.6 is the aperture. For this lens it is variable meaning that at different focal lengths the maximum aperture varies. for 18mm 3.5 and at 55 F5.6. Aperture is important for several factors. Depth of Field and pretty much how fast the lens is. At F3.5 your depth meaning at what distance items with still be in reasonable focus is smaller than at F16. Also at F3.5 you can use a shutter speed which is faster than at F16. Since it allows more light to the sensor/film.

So is a smaller F number better. In ways yes and other ways no. A lens at F1.4 is really fast and allows you to shoot in very low light situations. However if your subject needs lots of depth then it is not possible and hence why sensors can now allow for ISOs of 3200 with reasonable image quality.
06-22-2011, 03:23 PM   #10
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Thanks for the fast and decent reply guys. Haven't been able to delve to far in yet as I've got an exam today, and this camera/hobby is a reward for doing well and a nice de stresser hopefully

As far as the mm goes, it doesn't mean that 18-55 is a macro lens in that I can only focus on things up to 55m (5.5cm?!?!) away and the 300mm (30cm) does it? it doesn't seem like much range at all!
06-22-2011, 04:15 PM   #11
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No. It doesn't mean that. Not in the way you may be thinking. The smaller the number the wider the lens. To get an idea, form a rectangle with your hands, thumb to thumb, index finger to index finger. That will approximate the dimensions of a photo. Close one eye while looking through the center of that rectangle holding your hands close to your face. Now move your hands further away from your face. Note the different view inside that rectangle at the two different locations. The one closer to your face is the wide angle (18mm) type view, the one further away, could be thought of as the 300mm view (though that actual view will be smaller). All lenses have a minimum focus distance and it depends more on the actual lens than the 'mm'. Other factors are also affected by focusing distance.

Wider angle lenses are typically able to focus closer than long lenses (300mm). You can get pretty close with the 18mm end of the kit lens but it will not be macro. I think the kit lens has a 1:3 magnification ratio which means, that you will get 1/3 life size for your images. True macro lenses will do 1:1 or full life size. What that means is this. The image recorded on your sensor will be exactly the same size as the object you are photographing. At 1/3, it will be 1/3 the size of whatever you are photographing.

This, is close to a 1:1 macro photo (it's a rose) taken with a 50mm 1:1 preset Takumar (pentax) lens.



This photo was taken with a 20mm lens.



Both photos are the full actual photos taken. That is, many times one will crop (cut part away) a photo to focus more on a given subject. These photos are uncropped. There are a lot of ways to get macro photos but the two kit lenses aren't 'macro' or even close focusing lenses.

To further illustrate the Magnification ratio, look at these.

http://www.rolleiman.com/Photos/HelpandStuff/100mmf28WR/

These were done with a 100mm 1:1 macro at 1:1, 1:2, 1:3, and 1:4




Last edited by JeffJS; 06-22-2011 at 04:25 PM.
06-22-2011, 05:58 PM   #12
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Y'know, this "focal length" stuff can be quite confusing! It doesn't refer to the lens-to-subject distance, but rather the lens-to-frame (film or sensor) distance. So in a simple optical system, a 50mm lens that is focused to infinity ('way out there!) would sit 50mm from the film or sensor frame. A simple 300mm lens would be positioned 300mm from the frame, etc.

But camera lenses are NOT so simple, containing many internal lenses called 'elements'. Some elements may make them 'look' optically longer or shorter, so that 28mm lenses aren't too close and 300mm lenses aren't too long. Such elements are respectively called "wide-angle" or "retrofocus" groups, and "telephoto" groups. These, and other aspects of lens design, can make determining a lens' focal length an arcane art.

When a lens is focused to infinity, it sits closest to the frame. To focus on something closer, we move the lens away from the frame. A lens body is built with a "minimum focus distance", the furthest the lens can be extended. To focus closer, like into the macro range for greater magnification, we may need to add extension (tubes and/or bellows) behind the lens body.

And this is where "focal length" rules: A non-reversed lens can't focus closer than its focal length (FL), no matter how much extension we put on it for more magnification. And that close-focus distance is also where magnification is greatest. So if we have a lens of unknown FL, we can easily FIND the FL! Put the lens on extension, move towards a subject, and when the subject is sharp, the lens-to-subject distance is the focal length, voila!
_______________________________________________________________

Another important thang about focal length is angle-of-view or AOV. We say that a lens with FL the same as the diagonal of the camera frame is 'normal', giving roughly the same AOV as one human eye. On a Pentax dSLR with an APS-C sensor, that is about 28mm. (On a full-frame camera like a Pentax K1000, that 'normal' dimension is 43mm.) Lenses a bit shorter than normal are 'wide', for example 16 or 20 or 24mm on APS-C. Lenses with a bit greater FL than normal are 'long', like 40 or 55 or 85 or 105mm. Wide lenses see a wide AOV, long lenses take in a narrower view, etc.

Focal length and aperture have implications with focus, depth-of-field (DOF), sharpness / softness, all sorts of stuff, more than I'll discuss now. My recommendation: Get thee to a library. Read every book they have on photography. If possible, see the old TIME-LIFE LIBRARY OF PHOTOGRAPHY volume titled THE CAMERA. It's film-era info, but the principles still apply, and it illustrates quite well the interactions of focal length, distance, aperture, all that. Have fun!
06-23-2011, 08:01 AM   #13
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Wow, that's a lot of info Rio. One thing I did understand, though, was getting to a library. I go to the library as often as possible to look for explanatory/how-to books but to also look for photography books like the Time Life series or other collections of stills and just look and sometimes try to emulate.
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