Sigma Lens Question

[Guest belgian.blue]

I have a Pentax K1OO body with a Sigma DC 18-125 lens .. pretty much the lens is rubbish. I find it very hard to photograph Ivy, being a black dog, indoors and well, it can't photograph ANYTHING indoors with it. It is also pretty bad at shooting movement.

Yeah I'm really kicking myself for buying Pentax over Canon, but I spent a fair amount of money on my Pentax so I thought I'd up my lens, maybe. Depending on costs!

So, lens help pretty please ;)

[lappiemum]

I have a Pentax K1OO body with a Sigma DC 18-125 lens .. pretty much the lens is rubbish. I find it very hard to photograph Ivy, being a black dog, indoors and well, it can't photograph ANYTHING indoors with it. It is also pretty bad at shooting movement.

Yeah I'm really kicking myself for buying Pentax over Canon, but I spent a fair amount of money on my Pentax so I thought I'd up my lens, maybe. Depending on costs!

So, lens help pretty please ;)

Bb - I have a pentax k7 body and a 18 - 200 lens which I love. The body is solid and weather proof & has an internal dust filter & the lens gives me great close up options - Esp when taking dogs in motion pics! I would look at either upgrading your lens or do both lens & body but have to say I'm very happy with the brand.

[lappiemum]

Forgot to mention I have sigma lenses ;)

[kja]

It doesn't really matter so much about the brand of the lens, its limiting factor in low light is going to be its aperture value. You want something fast - 1.2, 1.4, 1.8. And even with those, in low light like in a house in the evening, you're going to most likely want some external flash happening, too.

You may find that you're always going to be fighting against the Pentax and that it might be a good idea to consider selling it and moving to one of the bigger fish in the pond like Canon or Nikon before you invest in a lot more glass which will make it tougher for you to change, should you choose to do so.

I have several Sigma lenses and I would not be without them. In particular, I adore my Sigma 30 1.4 - check to see if they make it in a Pentax mount. Even with 1.4 you're going to need extra light and a high ISO for those low-no light situations.

[Guest belgian.blue]

It doesn't really matter so much about the brand of the lens, its limiting factor in low light is going to be its aperture value. You want something fast - 1.2, 1.4, 1.8. And even with those, in low light like in a house in the evening, you're going to most likely want some external flash happening, too.

You may find that you're always going to be fighting against the Pentax and that it might be a good idea to consider selling it and moving to one of the bigger fish in the pond like Canon or Nikon before you invest in a lot more glass which will make it tougher for you to change, should you choose to do so.

I have several Sigma lenses and I would not be without them. In particular, I adore my Sigma 30 1.4 - check to see if they make it in a Pentax mount. Even with 1.4 you're going to need extra light and a high ISO for those low-no light situations.

Ah so it's more the Pentax that can't handle the low light, then the lens?

Hmm very tempting to sell the Pentax and treat myself ..

[kja]

It's probably a combination of both.

The camera body will dictate what ISO you can use and be happy with - some people have a higher tolerance for noise than others and some camera bodies have more pleasing noise at high ISOs.

The lens dictates how much light can get onto your sensor. A faster lens (1.4 is fast, 4.5 is slow) allows you to open the aperture and allow more light in a shorter time so they are more expensive and better for low light shooting. The trade-off - because everything in photography is a trade-off - is that you have a narrower depth of field: less of the image will be in the focus plane, sometimes only a few mm depending on your lens and distance to your subject. So this can make it tougher to get a sharp image, even if you get a good exposure.

[RottnBullies]

The lens dictates how much light can get onto your sensor. A faster lens (1.4 is fast, 4.5 is slow) allows you to open the aperture and allow more light in a shorter time so they are more expensive and better for low light shooting. The trade-off - because everything in photography is a trade-off - is that you have a narrower depth of field: less of the image will be in the focus plane, sometimes only a few mm depending on your lens and distance to your subject. So this can make it tougher to get a sharp image, even if you get a good exposure.

I love the way you explain things!

This Is what I seem to be having probs with now with the 50mm 1.8 Trying to get what I want to be In focus Is proving hard, If the eyes are in focus the nose Isn't and vice versa lol Any tips on how to judge that focus plain?! I can never tell properly In the viewfinder whether I got It right or not, only till I upload them I realize they're not focused, I have bad eyes

So sorry for the hyjack BB

[lappiemum]

Hi BB-

Its up to you but I've taken pics in very very low light conditions and the pics have worked out fine.

It may be that you do need a new body, but when I did my investigations recently (I've just bought my camera) I didn't feel that the Canon or Nikon were better than the Pentax I eventually bought

I agree that the lens is probably an issue - and yes, you may also need to upgrade your body - but I don't think Pentax sells crap cameras

taken inside, without a flash at night in really, really crap lighting

Edited August 17, 2010 by lappiemum

[Guest belgian.blue]

Thanks Lappiemum, can't view them at work but I'll have a look tonight.

How many pixels is the K7? Just googled and they look nice! Mine is only 6 I think but I did buy the camera over two years ago.

Maybe I will just take body and lens to a camera shop and see what they say, see what price a better lens is and then take action.

Thats OK RottnBullies

[Guest Tess32]

Long term, it's not the specific body that matters, you are buying a whole system. The Pentax cameras would be fine but they do not have the huge range of lenses that Canon & Nikon do and so your options are always going to be limited.

[Linda K]

also, unless you are determining the exposure settings yourself and taking control over what you camera is wanting to expose the shots at, you will find that the digital camera is trying to expose everything as 18% grey. That is why the camera will always make a black subject more a dark grey, and whites come out greyish as well - left to its own devices, a camera will try to overexpose the black and underexpose the white. So how do we avoid that. Have the camera on manual, and if shooting a black subject, if the camera is say trying to tell you to us a setting of 1/125 sec, then try 1/250 or 1/500 (ie underexpose what the camera is telling you to use, and then check the histogram afterwards to make sure that there are no areas of data loss.) For whites, you obviously go over what the camera is telling you to expose it as

Indoors shooting at night with no flash can be done, but you do need a camera really that can handle low light well - with my D700 or 5DII, I don't hesitate at going to ISO 6400, but with my old canon 10D, if I went above ISO 400 the noise was very evident.

Rootnbullies - how wide are you trying to shoot - it takes a lot of practice to get the handle of using the 1.8 wide open, try at F4 and work backwards from there - just because something can go wide open does not man you always need to shoot it like that. A depth of field calculator can be found here click that can help you work out how close you need to be and what aperture you can use, and still have what you want in focus - hope it is useful

[Guest belgian.blue]

Thanks Linda .. I always shoot in manual and it takes me about 15 minutes to set up as I'm not overly cluey about the settings ISO etc.

Capturing Badger inside the house is easy, he's not black but he doens't sit still

I will have a play around with it tonight with some of the ISO hints posted.

[RottnBullies]

Rootnbullies - how wide are you trying to shoot - it takes a lot of practice to get the handle of using the 1.8 wide open, try at F4 and work backwards from there - just because something can go wide open does not man you always need to shoot it like that. A depth of field calculator can be found here click that can help you work out how close you need to be and what aperture you can use, and still have what you want in focus - hope it is useful

Shooting pretty wide at 2.2 but I needed It due to crappy backgrounds, I know I need loads and loads more practice seeing as my subject Is white headed also and I'm having probs with that too even though I shoot her In the shade! And no I'm yet not comfortable shooting In full manual yet so it's Tv or Av for quite some time for me

Thanks for the link I will check It out. Will also try and work backwards with F4

[kja]

Rottn - you'll have far more luck with full manual than Av or Tv, imho. And it's not that hard.

Select your aperture, leave it alone.

Now select your shutter speed - underexposed? Slow the shutter. overexposed - select a faster speed.

You've just shot in full manual even though you are only changing ONE setting. Don't let the camera guess for you - YOU guess and see what happens.

You will learn much more quickly how to control the various lighting conditions in the frame to suit your eye instead of hoping the camera can read your mind (and the scene).

I promise, it's not as horrible as it sounds and you'll be very surprised how quickly you get an "ah-ha" moment & progress to being able to flip through to the right settings for your scene.

As for needing to blur out the backgrounds, the only way to deal with the eyes and nose in focus at the same time and still lose the background is to back up away from your subject and move your subject away from the background. A wide open aperture (let's call it anything wider open than f4) just isn't going to give you the amount of centimeters you need if you're all up close. But if you have adequate distance, even f2.2 or f1.4 will give you a surprising amount of space to work with - of course, you have to have that distance which often isn't feasible (or desirable).

If you're shooting the same subject over and over - measure the distance you want in focus and then use on of the Depth of Field calculators on the web to give you a starting point.

Edited August 17, 2010 by kja

[RottnBullies]

Thanks for all your tips kja will give It another try In full Manual....again as I failed miserably last few goes :D

[SchnauzerBoy]

I think kja has pretty much explained it here... but put the ISO up as high as it will go before it gets too noisy (400 is probably enough on your camera).

Not sure if pentax do a 50mm 1.8 or any 1.4 lenses which are more aimed at pro levels (hence the price) but the 50mm 1.8 is reasonably priced.

A powerful flash would also help to freeze the motion and allow you to control your depth of field through the manual settings better.

As others have said though, you buy into a system rather than a specific camera (i've moved from a D80 to a D700 to improve performance at things like this!).

In a studio environment where everything is controlled almost all cameras can get the same results.

[Guest belgian.blue]

Is anyone else not a fan of using a flash? I really don't like using one.

Can someone explain noise? I've heard it a lot recently.

[kja]

Noise = all the funky dots you see, especially in shadows. Some noise has colour - specks of red, orange, yellow, green etc. Some noise is easily removed with noise reduction software - LR3s new options are excellent now. Some noise can be really difficult and/or time consuming to remove. Some people don't care about noise at all, some are crazy anal about it. It's totally up to your own eye as to what is acceptable and it will likely vary from photo to photo.

Googling for images with noise or some such should show you a zillion examples as will heading over to the pixel peeping at POTN.

Flash = used well is wonderful. Pop up flash from your camera body is great if it's all you've got and must get the shot, but it's almost never going to look lovely I love using flash - but I always use it for a reason and have the end product in mind. I don't just fire it full tilt straight on and I can't tell you the last time I had to use pop up flash.

Attached is flash fired from my baby Olympus 720SW camera - it's a little harsh, but without it the doglets would have been too dark and/or the sky would have been more blown instead of blue.

HTH

Edited August 19, 2010 by kja