Prime lens in low light 50mm

fevbusch · 02-06-2007, 05:33 AM

I was happy with the low light performance of my 50mm pentax 1.7 on my K100D body (although it was manual and I found it much too difficult to focus).
I'm considering the Sigma 50mm 2.8 EX Macro autofocus lens and am wondering if the low light performance will be as good as the Pentax 1.7 in indoor situations. Also, will the Sigma focus sharply if I do not really want to get as close as 1:1 but stay from 8" to 18" away. Appreciate any comments. Thanks, Freddy

trog100 · 02-06-2007, 06:40 AM

2.8 isnt 1.7.. its one and a half f-stops slower.. the sigma will be sharp enough but isnt as fast..

trog

fevbusch · 02-06-2007, 08:17 AM

Thanks, Trog. Also, about my comment about shooting 8" to 18" away instead of 1:1. Will the Sigma still focus as sharply. Also, would the 50mm Sigma work well with flash indoors. Freddy

**NaClH2O** · 02-06-2007, 08:34 AM

Freddy, I don't own that particular lens but going by my Tamron 90mm macro, I will give a highly qualified "it should" at least my Tamron does. In fact one of the reasons I like the lens so much is that it gives great close up portrait shots and I don't have to be in the subject's face to get them. The only limiting factor is available light. My DS (and everybody else's it seems) is notoriously slow focusing in low light situations. But with "sufficient" light I have no problems with crisp accurate focus.

NaCl(of course if you want to count eyelashes, you can get up close)H2O

egordon99 · 02-06-2007, 08:45 AM

If the light is really low (indoors at night but with normal house lighting), f/2.8 can be a bit too slow. I love my Tamron 28-75mm f/2.8, but if the lighting gets really low, I'm usually stuck at f/2.8, ISO1600 and shutter speeds of only 1/50 or so (too slow to stop motion/camera shake). This is when I stick my 50mm f/1.4 on. This gives me two stops, so I can go to f/1.4, ISO800 and 1/100s.

If I'm indoors and there is alot of sunlight coming in, f/2.8 is usually decent enough.

fevbusch · 02-06-2007, 08:48 AM

Thanks, H2O. What is the fstop range of your Tamron 90mm. Also, please forgive my ignorance, but what does DS mean. Freddy

**NaClH2O** · 02-06-2007, 09:09 AM

Hi Freddy, the Tamron goes from f2.8 to 32. Same as the Sigma, I think. "DS" is my camera, the *ist DS, the first sub 1000usd DSLR pentax produced. Mine is ancient and elderly in digital terms, over two and a half years old!!!

NaCl(a bit long in the tooth but it still takes great pictures)H2O

trog100 · 02-06-2007, 12:19 PM

what sort of pitures do u wish to take freddy..

some would be examples.. lets go at it from a different angle..

trog

jnorth · 02-06-2007, 12:56 PM

Originally posted by fevbusch

I was happy with the low light performance of my 50mm pentax 1.7 on my K100D body (although it was manual and I found it much too difficult to focus).
I'm considering the Sigma 50mm 2.8 EX Macro autofocus lens and am wondering if the low light performance will be as good as the Pentax 1.7 in indoor situations. Also, will the Sigma focus sharply if I do not really want to get as close as 1:1 but stay from 8" to 18" away. Appreciate any comments. Thanks, Freddy

Are you happy with that 1.7 dialed into 2.8? In a 50, 2.8 just isn't fast enough for some of the scenarios that I would like to use it in. Now if it's a zoom in the 28-70 range I'd be happy with a constant 2.8.

02-06-2007, 05:33 AM	#1
fevbusch Pentaxian Join Date: Jan 2007 Location: Brooklyn, New York Photos: Gallery \| Albums Posts: 1,064	Prime lens in low light 50mm I was happy with the low light performance of my 50mm pentax 1.7 on my K100D body (although it was manual and I found it much too difficult to focus). I'm considering the Sigma 50mm 2.8 EX Macro autofocus lens and am wondering if the low light performance will be as good as the Pentax 1.7 in indoor situations. Also, will the Sigma focus sharply if I do not really want to get as close as 1:1 but stay from 8" to 18" away. Appreciate any comments. Thanks, Freddy

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02-06-2007, 06:40 AM	#2
trog100 Veteran Member Join Date: Dec 2006 Location: UK Posts: 642	2.8 isnt 1.7.. its one and a half f-stops slower.. the sigma will be sharp enough but isnt as fast.. trog

02-06-2007, 08:17 AM	#3
fevbusch Pentaxian Join Date: Jan 2007 Location: Brooklyn, New York Photos: Gallery \| Albums Posts: 1,064 Original Poster	Thanks, Trog. Also, about my comment about shooting 8" to 18" away instead of 1:1. Will the Sigma still focus as sharply. Also, would the 50mm Sigma work well with flash indoors. Freddy

02-06-2007, 08:34 AM	#4
NaClH2O Site Supporter Join Date: Sep 2006 Location: Bronx NY Photos: Gallery \| Albums Posts: 5,631	Freddy, I don't own that particular lens but going by my Tamron 90mm macro, I will give a highly qualified "it should" at least my Tamron does. In fact one of the reasons I like the lens so much is that it gives great close up portrait shots and I don't have to be in the subject's face to get them. The only limiting factor is available light. My DS (and everybody else's it seems) is notoriously slow focusing in low light situations. But with "sufficient" light I have no problems with crisp accurate focus. NaCl(of course if you want to count eyelashes, you can get up close)H2O

02-06-2007, 08:45 AM	#5
egordon99 Inactive Account Join Date: Dec 2006 Location: Outside of Philly Posts: 1,561	If the light is really low (indoors at night but with normal house lighting), f/2.8 can be a bit too slow. I love my Tamron 28-75mm f/2.8, but if the lighting gets really low, I'm usually stuck at f/2.8, ISO1600 and shutter speeds of only 1/50 or so (too slow to stop motion/camera shake). This is when I stick my 50mm f/1.4 on. This gives me two stops, so I can go to f/1.4, ISO800 and 1/100s. If I'm indoors and there is alot of sunlight coming in, f/2.8 is usually decent enough.

02-06-2007, 08:48 AM	#6
fevbusch Pentaxian Join Date: Jan 2007 Location: Brooklyn, New York Photos: Gallery \| Albums Posts: 1,064 Original Poster	Thanks, H2O. What is the fstop range of your Tamron 90mm. Also, please forgive my ignorance, but what does DS mean. Freddy

02-06-2007, 09:09 AM	#7
NaClH2O Site Supporter Join Date: Sep 2006 Location: Bronx NY Photos: Gallery \| Albums Posts: 5,631	Hi Freddy, the Tamron goes from f2.8 to 32. Same as the Sigma, I think. "DS" is my camera, the *ist DS, the first sub 1000usd DSLR pentax produced. Mine is ancient and elderly in digital terms, over two and a half years old!!! NaCl(a bit long in the tooth but it still takes great pictures)H2O

02-06-2007, 12:19 PM	#8
trog100 Veteran Member Join Date: Dec 2006 Location: UK Posts: 642	what sort of pitures do u wish to take freddy.. some would be examples.. lets go at it from a different angle.. trog

02-06-2007, 12:56 PM	#9
jnorth Senior Member Join Date: Dec 2006 Location: Vancouver BC Posts: 230	Originally posted by fevbusch I was happy with the low light performance of my 50mm pentax 1.7 on my K100D body (although it was manual and I found it much too difficult to focus). I'm considering the Sigma 50mm 2.8 EX Macro autofocus lens and am wondering if the low light performance will be as good as the Pentax 1.7 in indoor situations. Also, will the Sigma focus sharply if I do not really want to get as close as 1:1 but stay from 8" to 18" away. Appreciate any comments. Thanks, Freddy Are you happy with that 1.7 dialed into 2.8? In a 50, 2.8 just isn't fast enough for some of the scenarios that I would like to use it in. Now if it's a zoom in the 28-70 range I'd be happy with a constant 2.8.