[betaPhoto]

I found the 18-55/3.5-5.6 too soft for a general lens for beginning photography, it didn't inspire me to want to learn and use a DSLR. Others use it and are happy with it, try it and find out.

If the lens bores you or turns you off, decide if you take a lot of quick pictures of changing subjects or static subjects in a controlled envirnment or both. For changing subjects or both get 1 or 2 zooms and then 1or 2 primes. For mostly static subjects get 2 to 3 primes and then a zoom. If you like macro (very close up) make one prime a macro.

Next figure out a budget for your lenses. If it is a high budget, get FA Limited primes or DA*'s or Limited primes and/or zooms.
Examples: 1) DA* 16-50 and DA* 50-135 and a FA 50/1.4 or FA 77 Limited for portraits.
2)FA * 31 or FA*43 and FA*77 and DA* 16-50 or DA* 50-135
3)DA 21 Limited and DA 40 Limited and DA 70 Limited and DA* 50-135
The point is, if you have a high budget, get 3 to 4 great lenses and see which ones you use most. Then sell the ones not being used and if interested get a few other great lenses. You might lose a few hundred on the 1 or 2 you don't use, but that's not much if money isn't an issue to you (or buy them used and sell them used and you will lose less).

If you have a low or lower budget, things get a lot more interesting. Most of the above glass is out of range until you know exactly what you want, and that takes time and personal experience. After which, get 1 or 2 great lenses specified to what you need and want, without forgetting about all the older glass which can take amazing shots.


So how do you get experience on a lower budget? Look for a few low cost gems on the used market.
1) F 35-70/3.5-4.5 ~$50.00 - Mid Range plus a little extra - (with a fun macro setting)
2) DA 16-45/4 ~$250.00 - Wide Angle to Mid Range
3) F 70-210/4-5.6 ~$125.00 - Mid Tele to Tele
4) A 50/1.7 ~$85.00 - Portaits (for head shots use #1) - (Manual Focus, Auto Aperature)
Or, if you like, just use the kit lens (not my preference).

Also: F5.6 is slow
F4.0 is mid speed (often fast enough especially on the KX)
F2.8 is moderately fast
F2.0 is fast
F1.4 & 1.7 is extemely fast

Lastly, don't forget amazing pictures can be taken on "almost" any lens.

[yeatzee]

must have IMO is the pentax M 50mm F/1.7.

Its super sharp, its fast, costs under $50, and is manual focus/uses an aperture ring. Buying this lens will help you to understand photography much quicker and it will all be hands on. Instead of the lens focusing for you, you have to focus it. Instead of the camera choosing settings for you you have to pick what F-stop you want to use. And while doing this you will physically be able to see what F-stop's mean and what they do by simply holding the M 50mm up to you face and turning the aperture ring. This in conjunction with manual focusing will help you to understand DOF and its correlation between F-stops.

Therefor I say buy this lens (off ebay or whatnot) and play with it. After time you will understand Depth of field (DOF), F-stops, manual focusing, manual mode (on camera), etc....

It will also wet your appetite for a fast 50mm and you will soon realize whether that is the focal length for you or not. When your done with it and you've found your not in love (highly unlikely....its one of my favorite lenses and I will never sell mine) put it back on ebay. Its a fairly wanted lens, and you shouldn't have any trouble selling it.

Here's just a normal indoor shot in bad lighting to give you an idea of what this lens can do in amateur hands:

Edit: I haven't been shooting DSLR's for all that long (a little over a year) but this is how I did it: Played with a friends Pentax DSLR for a while with kit lens and figured a DSLR was for me. I bought a K200d with kit lens and shot with it every day for several months. I started with M mode instead of the green modes and quickly learned how it all works (how F-stop affects amount of light hitting sensor, how F-stops change DOF, how F-stops change sharpness, motion blur, etc...). Luckily pentax's kit lens focuses fairly close, so I soon found nearly every shot was of a flower or insect at the lenses minimum focusing distance. It just wasn't close enough for me so after much deliberation I bought a sigma 105mm macro. It exactly what I wanted/needed and its by far my most used lens (I'd say 90%). I shoot macro almost exclusively now..... your mileage will vary.
I than bought the M 50mm F/1.7 because 105mm was to much for indoor shots. Like I said, this lens will never be sold by me.....its amazing period. Than I realized wildlife was just to far away most of the time for my 105mm to capture them so i bought a used DA 55-300mm for the 300mm which has worked out great. After that, because of my love for the M 50mm F/1.7, I found a cheap M 200mm on ebay and purchased that. Sure enough I didn't like it all that much. I preferred my DA 55-300mm at 200mm to the M 200mm. Despite this it turns out the M 50mm F/1.7 reversed on the M 200mm works great for close up macro (the built in good hold the lenses front element even with the M 200mm front element) so it will not be sold either. From there I got the M 85mm as a portrait lens...... and what a portrait lens it is. Again, this will never be sold.

Well there ya have it

[Softsoap]

I found the 18-55/3.5-5.6 too soft for a general lens for beginning photography, it didn't inspire me to want to learn and use a DSLR. Others use it and are happy with it, try it and find out.

If the lens bores you or turns you off, decide if you take a lot of quick pictures of changing subjects or static subjects in a controlled envirnment or both. For changing subjects or both get 1 or 2 zooms and then 1or 2 primes. For mostly static subjects get 2 to 3 primes and then a zoom. If you like macro (very close up) make one prime a macro.

Next figure out a budget for your lenses. If it is a high budget, get FA Limited primes or DA*'s or Limited primes and/or zooms.
Examples: 1) DA* 16-50 and DA* 50-135 and a FA 50/1.4 or FA 77 Limited for portraits.
2)FA * 31 or FA*43 and FA*77 and DA* 16-50 or DA* 50-135
3)DA 21 Limited and DA 40 Limited and DA 70 Limited and DA* 50-135
The point is, if you have a high budget, get 3 to 4 great lenses and see which ones you use most. Then sell the ones not being used and if interested get a few other great lenses. You might lose a few hundred on the 1 or 2 you don't use, but that's not much if money isn't an issue to you (or buy them used and sell them used and you will lose less).

If you have a low or lower budget, things get a lot more interesting. Most of the above glass is out of range until you know exactly what you want, and that takes time and personal experience. After which, get 1 or 2 great lenses specified to what you need and want, without forgetting about all the older glass which can take amazing shots.


So how do you get experience on a lower budget? Look for a few low cost gems on the used market.
1) F 35-70/3.5-4.5 ~$50.00 - Mid Range plus a little extra - (with a fun macro setting)
2) DA 16-45/4 ~$250.00 - Wide Angle to Mid Range
3) F 70-210/4-5.6 ~$125.00 - Mid Tele to Tele
4) A 50/1.7 ~$85.00 - Portaits (for head shots use #1) - (Manual Focus, Auto Aperature)
Or, if you like, just use the kit lens (not my preference).

Also: F5.6 is slow
F4.0 is mid speed (often fast enough especially on the KX)
F2.8 is moderately fast
F2.0 is fast
F1.4 & 1.7 is extemely fast

Lastly, don't forget amazing pictures can be taken on "almost" any lens.

Hi thanks for ALL your info! What is the differance.iyo, with the 1.4 Vs 1.7 Lenses?

[twokatmew]

A 1.4 lets in more light than a 1.7 and has an even shallower depth of field.

BTW, I'm learning lots about DoF even without a manual lens. Just shoot aperture priority (Av). When I want to play with DoF, I use Av. When I want to freeze or blur motion, I use Tv. When I just want a nice well-balanced shot, I use Program mode.

[betaPhoto]

Hi thanks for ALL your info! What is the differance.iyo, with the 1.4 Vs 1.7 Lenses?

The 1.4 lets in double the light at 1.4 only (meaning if you need 3200 ISO @ 1.7, then you can set the lens to 1.4 and use 1600 ISO. It's called 1 F-stop faster), all the other settings on both lenses are equal.

F1.4 is somewhat hard to use because not very much of the picture is in focus (shallow depth of field). At a modestly close distance maybe 8 inches depth of focus (from the front of the nose to the back of the head, maybe even less), everything else is blurry (called bokeh). I don't use F1.4 on my lense much at all.

Also, @ F1.4 the focused part is not very sharp but @ F2.0 and higher the sharpness starts to increase dramatically in both lenses. So it's really a matter of preference which lens you like best. Since you are beginning, I thought you might like an easy to use manual focus A50/1.7 (A = auto aperature, M = manual aperature) for less money. The quality of the pictures should be high with either one if you do it right. If you really like using this type of lense, try another version in the future.

[JeffJS]

The 1.4 lets in double the light at 1.4 only (meaning if you need 3200 ISO @ 1.7, then you can set the lens to 1.4 and use 1600 ISO. It's called 1 F-stop faster),

No it isn't.. f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/45, f/64, f/90, f/128

f1.7 is half a stop slower than the f1.4 which is half a stop slower than the f1.2.

That said, if you want a fast fifty, I don't think you can go wrong with the Pentax A 50 f1.7. The M version is nice too but using the A is loads easier because you can use all the auto exposure programs of your camera.

[sterretje]

I just got my Pentax and I have 2 lenses so far. I have the 18-55mm F3.5-5.6 AL and also a Sigma 70-300mm F4-5.6 DG Macro...

Congratulations

So, I needs your help..I am new to the DSL and Lenses world, so I really don't get all the specks yet, like what does F3.5-5.6 mean? Please be kind..

You have a zoom lens with numbers 18-55 and 3-5.4-5. The former indicates the focal length and the latter the maximum (read widest) aperture. This widest aperture varies depending on the focal length (for this specific lens as well as for your Sigma; there are zoom lenses with a constant aperture). It is 3.5 at 18mm and 4.5 at 55mm and somewhere in between for the focal lengths in between that.

The aperture in combination with the shutter speed determines the amount of light that will reach the sensor. The ISO setting determines how much light is actually needed for correct exposure. As long as you stay away from 'funny' modes like B and M the camera will do all the calculations for you. If you use e.g. Av, you select the aperture and the camera will adjust the shutter speed that will result in enough light on the sensor for the selected ISO. A selected aperture of e.g 4 and a shutter speed of 1/60s will give the same amount of light on the sensor as and aperture of 5.6 and a shutter speed of 1/30s.

Aperture also influences depth of field (DOF) which indicates how much in the foreground and background seems to be in focus while focusing on something in between.

In low light, you can open the aperture wider (you will get more light in with the same shutter speed but DOF changes) or select a longer shutter speed (again, there will be more light as the time is longer but moving subjects might show blurred because they don't stay in one position while the shutter is open) or select a higher ISO so less light is needed (higher ISO however implies more noise).

I suggest that you start reading up on the items that I have marked italic blue.

Also, I hear a must have lenses is the 50 mm f 1.4??

As the question is about the 3.5-4.5 and 50/1.4, there are maximums on aperture (the 3.5-4.5 in the case of the kit lens) so you can not open it up wider. And that is where e.g. the 1.4 of the 50/1.4 comes in handy. If the kit lens at 50mm indicates that it needs a shutter speed of 1/8sec at ISO3200 while the aperture is wide open, you can take the shot with 1/60sec with the 50mm/1.4 and aperture set to 1.4 so you have to worry less about camera shake; but it's a prime (fixed focal length) so you might only be able to get half a person in the picture because you can not get far away enough and might need an 18/1.4 as well And DOF at 1.4 can be very shallow resulting in only the eyes of a person being in focus and the rest (like nose and ears) out of focus.

I agree with the others that you just should start shooting and based on experience determine what you need. You might find low light limitations in which case the 50mm/1.4 might help if you indeed shoot a lot at the longer end of the kit lens but a flash might be the more universal option. Or you might find that you might need a wider lens than the 18mm in which case the 50mm is a (close to) total waste.

[betaPhoto]

No it isn't.. f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/45, f/64, f/90, f/128

f1.7 is half a stop slower than the f1.4 which is half a stop slower than the f1.2.

Thanks for the correction, I messed it up in my mind.

[betaPhoto]

Congratulations

You have a zoom lens with numbers 18-55 and 3-5.4-5. The former indicates the focal length and the latter the maximum (read widest) aperture. This widest aperture varies depending on the focal length (for this specific lens as well as for your Sigma; there are zoom lenses with a constant aperture). It is 3.5 at 18mm and 4.5 at 55mm and somewhere in between for the focal lengths in between that.

The aperture in combination with the shutter speed determines the amount of light that will reach the sensor. The ISO setting determines how much light is actually needed for correct exposure. As long as you stay away from 'funny' modes like B and M the camera will do all the calculations for you. If you use e.g. Av, you select the aperture and the camera will adjust the shutter speed that will result in enough light on the sensor for the selected ISO. A selected aperture of e.g 4 and a shutter speed of 1/60s will give the same amount of light on the sensor as and aperture of 5.6 and a shutter speed of 1/30s.

Aperture also influences depth of field (DOF) which indicates how much in the foreground and background seems to be in focus while focusing on something in between.

In low light, you can open the aperture wider (you will get more light in with the same shutter speed but DOF changes) or select a longer shutter speed (again, there will be more light as the time is longer but moving subjects might show blurred because they don't stay in one position while the shutter is open) or select a higher ISO so less light is needed (higher ISO however implies more noise).

I suggest that you start reading up on the items that I have marked italic blue.

As the question is about the 3.5-4.5 and 50/1.4, there are maximums on aperture (the 3.5-4.5 in the case of the kit lens) so you can not open it up wider. And that is where e.g. the 1.4 of the 50/1.4 comes in handy. If the kit lens at 50mm indicates that it needs a shutter speed of 1/8sec at ISO3200 while the aperture is wide open, you can take the shot with 1/60sec with the 50mm/1.4 and aperture set to 1.4 so you have to worry less about camera shake; but it's a prime (fixed focal length) so you might only be able to get half a person in the picture because you can not get far away enough and might need an 18/1.4 as well And DOF at 1.4 can be very shallow resulting in only the eyes of a person being in focus and the rest (like nose and ears) out of focus.

I agree with the others that you just should start shooting and based on experience determine what you need. You might find low light limitations in which case the 50mm/1.4 might help if you indeed shoot a lot at the longer end of the kit lens but a flash might be the more universal option. Or you might find that you might need a wider lens than the 18mm in which case the 50mm is a (close to) total waste.

Just to be clear for the OP, the kit lens is 3.5-5.6 not 3.5-4.5.

The F 35-70 is 3.5-4.5, and the 35-55 part of the lens (equal to the long end of the kit) is 3.5-4.0 (and the kit is probably ~ 4.5-5.6). Meaning the kit is about 1 stop slower with less sharpness, contrast and 3D effect.

[fractal]

I think there should be a general rule that all first-time DSLR buyers shouldn't buy any lenses beyond the kit lens for 6 months.

Nor should they put up threads titled, 'What is the best lens to buy'. I don't mean to sound harsh but there seems to be a lot of these types of threads going up lately. Our forum is a wealth of information, all of which can be found by hitting the search button. It will be enough reading to make your hair go grey.

[interested_observer]

You have received wonderful advice here on the Forum. You can go broke quickly buying all the must haves. The only must have is the one that you use for the type of photography that interests you...

On the topic of fast lenses, here are a couple threads that illustrate what a fast lens can do for you. Some folks are very interested in this type of images, while others are not. Fully dependent on the individual and their particular interests...

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/78029-melbourn...omparison.html

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/74819-post-you...31-2-only.html

[Clicker]

I just got my Pentax and I have 2 lenses so far. I have the 18-55mm F3.5-5.6 AL and also a Sigma 70-300mm F4-5.6 DG Macro...

So, I needs your help..I am new to the DSL and Lenses world, so I really don't get all the specks yet, like what does F3.5-5.6 mean? Please be kind..

Also, I hear a must have lenses is the 50 mm f 1.4??

I love taking indoor and outdoor Family shots. Wedding and Baby's I would like to do also..Thanks ..

I would say for what you do, you only need one

[Rondec]

Basically as mentioned above, there are two kinds of lenses: zooms and primes. Primes only have one focal length, but tend to be sharper, faster, and smaller than zooms. If you think you want to try a prime, probably the best thing is to shoot with your current lenses for a little while and then look at your photos and see what focal length you like best. Some love wide angles at 25-30mm and some like something longer in the 70mm range.

As a portrait lens, I personally would recommend either the DA *50-135 -- very sharp, excellent throughout the range, or the DA 70. The FA 50 is a sweet lens, but I have to confess that the focal length doesn't work very well for me personally. Feels too long to shoot a lot of indoor stuff in my home and a little too short for portraits. But that is just me. I think you don't have enough information yet to make an informed decision about your next lens. If you have to buy one now, choose one of the DA limiteds, but I would really recommend you wait.

[Hello_Photo]

Based on your stated goals, I think the best bang for your photographic buck may be an external flash, rather than a lens.

I know this is a lens forum, but hear me out on this.

In my experience, the only way to freeze action indoors (kids qualify as action subjects) is to use a flash. My first kit included the Sigma 17-70 (spec'd at F2.8-4.5, but between 21mm and 63mm, it's a F3.5-4) and the Pentax 360 flash. For indoor shots in confined spaces (unless you live in a mansion, most houses qualify here), I could blast the flash off the ceiling and get very sharp images of moving subjects in natural-looking lighting (no on-board or direct-flash shadows behind my subjects). Remember, the duration of a flash burst is measured in 1/10,000's of a second, so most of the exposure comes from the flash (although the mix of natural vs flash light can be controlled with shutter speed). As a result, it is much easier to freeze motion with a flash, than with a fast shutter speed (which a fast lens helps to achieve). Also, keep in mind that a large aperture means a narrow depth of field, which can be used for good artistic effect, but also makes focussing more difficult to control, so your "keeper rate" usually goes down with larger apertures. There are also times when I would find it frustrating to have to choose between more depth of field (say to get two people in focus) and freezing motion. With an external flash, you get both.

An external flash also opens-up new artistic possibilities. I believe all current Pentax DSLRs support wireless flash, which allows you to put the flash somewhere off-camera, to help get the soft, directional light that portrait photographers kill for. The on-camera flash acts as a trigger for the remote slave, so as long as the external flash's sensor can "see" the pre-flashes from the on-camera flash, you're good (and, it's way cheaper than radio-poppers). Don't underestimate how big a deal this is. When I discovered how many new options this simple trick gave me, I was hooked for life. Just be sure to use the on-camera flash in "commander" mode, not "master"; otherwise, the on-camera flash will still contribute to the exposure and you'll get unflattering shadows behind your subjects.

My one lesson learned from the 360 flash, is that I wish I had popped for the 540 before the price increase. Why? The 360 doesn't have a swivel head and the 540 does. If I'm not mistaken, the 540 will also recycle faster at a given level of light output - can anyone confirm this? Being able to swivel the head allows you to shoot in portrait orientation and bounce the light off the ceiling. You can also play around with bouncing the light off of walls (even behind you) more easily. Of course, this only matters when the flash is mounted on the camera, so wireless slaving can be a viable workaround.

I'm not saying fast lenses don't have there place (I own the 77mm F1.8 ltd and love it), but IMHO, an external flash broadens your photographic horizons more.

Good luck!

[Softsoap]

I totally appreciate all your responses. I have learned alot from your experiences. That is why I posted here instead of the SEARCH button. I am more personal that that and you learn more....