Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Sigma Lens
#1
(Mar 17, 2015, 11:11)JohnBax Wrote:
(Mar 17, 2015, 08:44)EnglishBob Wrote: The F Stop just effects the amount of light coming in, and the DoF of course.  A Smaller sensor does capture less of that light than a full frame would, howeverit still benefits from the extra light a larger hole lets in.

I wouldn't day it's wasting money to buy fast lenses, as they are still superior to the slower lens you would use instead.  And you don't multiply by the same number as you would for focal length.

Tony Northrup has a very detailed video on F Stop and sensor size on YouTube.

Thanks for the prompt replies I do appreciate them.  It was Tony Northrup that set me off with this.  His theory is that as the focal length changes with the smaller sensors then the F number must change with the calculation that the F no is equal to the focal length divided by the aperture diameter but in my mind the physical length of the lens and the size of the aperture do not change then the F no must be as stated on the lens, hence my question to get other opinions on this point.  The other question this raises for me is that if a lens is made for a small sensor i.e. the Sony DT range why is the focal length not as stated as there is no cropping of the image on the sensor?


Hi  I am thinking about buying a Sigma wide angle lens for my nikon D 3200 .The two lens that interest me are the 10-20 f3.5 ex dc HSM and the 17-50 f2.8 ex dc os,taking in to account the crop factor which in the opinion of other members would be the best purchase ?    Many thanks MBS
Reply

#2
(Mar 25, 2017, 12:31)MBS Wrote: Hi  I am thinking about buying a Sigma wide angle lens for my nikon D 3200 .The two lens that interest me are the 10-20 f3.5 ex dc HSM and the 17-50 f2.8 ex dc os,taking in to account the crop factor which in the opinion of other members would be the best purchase ?    Many thanks MBS

It might depend on what you already have - do you have any lenses that overlap either (or both) of those lens ranges?

As a general point, the 17-50mm is a standard zoom, covering the focal lengths of a typical kit lens (but with better quality), from moderate wide-angle up to short (portrait) telephoto - 26-75mm full-frame equivalent; whereas the 10-20 is a more specialised ultra-wide lens - 15-30mm FF equiv. Therefore the 17-50mm could stay on the camera most of the time, but the 10-20mm is more likely to have occasional uses.

Cheers.
Philip
Reply
#3
(Mar 25, 2017, 18:48)UMrB Wrote:
(Mar 25, 2017, 12:31)MBS Wrote: Hi  I am thinking about buying a Sigma wide angle lens for my nikon D 3200 .The two lens that interest me are the 10-20 f3.5 ex dc HSM and the 17-50 f2.8 ex dc os,taking in to account the crop factor which in the opinion of other members would be the best purchase ?    Many thanks MBS

It might depend on what you already have - do you have any lenses that overlap either (or both) of those lens ranges?

As a general point, the 17-50mm is a standard zoom, covering the focal lengths of a typical kit lens (but with better quality), from moderate wide-angle up to short (portrait) telephoto - 26-75mm full-frame equivalent; whereas the 10-20 is a more specialised ultra-wide lens - 15-30mm FF equiv. Therefore the 17-50mm could stay on the camera most of the time, but the 10-20mm is more likely to have occasional uses.

Cheers.
Philip
Reply
#4
MrB
(Mar 25, 2017, 12:31)MBS Wrote: Hi  I am thinking about buying a Sigma wide angle lens for my nikon D 3200 .The two lens that interest me are the 10-20 f3.5 ex dc HSM and the 17-50 f2.8 ex dc os,taking in to account the crop factor which in the opinion of other members would be the best purchase ?    Many thanks MBS

It might depend on what you already have - do you have any lenses that overlap either (or both) of those lens ranges?

As a general point, the 17-50mm is a standard zoom, covering the focal lengths of a typical kit lens (but with better quality), from moderate wide-angle up to short (portrait) telephoto - 26-75mm full-frame equivalent; whereas the 10-20 is a more specialised ultra-wide lens - 15-30mm FF equiv. Therefore the 17-50mm could stay on the camera most of the time, but the 10-20mm is more likely to have occasional uses.

Cheers.
Philip
Reply
#5
Hi. Philip Thanks for the reply,I have a 50-1.8.   70-300.  50-500 I intend to part exchange the 70-300 as the50-500 overlaps it,what lens do you use for wide angle photograghy and what lens would you recommend apart from the Sigma 10-20mm
                      
                        Regards Mick (MBS )
Reply
#6
Hello Mick.

From your list in post #5 it seems that you do not have a standard zoom, so perhaps you would appreciate the Sigma 17-50mm as your next purchase.

My choice is rather unusual, as the zoom most often attached to my APS-C camera is now a full-frame Pentax 28-105mm. I just find that most of the things I photograph fall very nicely into that range (full-frame equivalent = 42-158mm). The APS-C sensor is using the best part of that full-frame lens image, so the image quality is very good. For wide-angle shots, I either take along a small 21mm prime or a Tamron 10-24mm zoom. If I don't have those with me, and cannot get far enough back to fill the frame with the subject, I get wider angles by shooting several overlapping shots, and stitching them together later on the computer, using the Microsoft ICE (Image Composite Editor) free software.

Here is one of those stitched images from yesterday, because I wanted the tree shadow in the foreground - 3 shots (bottom, middle, top) taken at 28mm with the 28-105 zoom.

Cheers.
Philip


Attached Files Image(s)
   
Reply

#7
(Mar 26, 2017, 07:58)MBS Wrote: ....what lens would you recommend apart from the Sigma 10-20mm

Not being sufficiently experienced and qualified to recommend, I can only put forward suggestions for consideration. The following images are examples from the Tamron 10-24mm, and remember that I have this lens because its range fits well alongside my 28-105mm zoom. The first is at 16mm and the second at 10mm on an APS-C camera (24mm and 15mm full-frame equivalent). The images were adjusted in PaintShop Pro X8.

Cheers.
Philip


Attached Files Image(s)
       
Reply
#8
Hi Philip  Nice photos ,going to Jessops to look at the Tamron 10-24 thanks agin for your input.
                 Regards Mick (MBS)
Reply
#9
(Mar 25, 2017, 12:31)MBS Wrote:
(Mar 17, 2015, 11:11)JohnBax Wrote:
(Mar 17, 2015, 08:44)EnglishBob Wrote: The F Stop just effects the amount of light coming in, and the DoF of course.  A Smaller sensor does capture less of that light than a full frame would, howeverit still benefits from the extra light a larger hole lets in.

I wouldn't day it's wasting money to buy fast lenses, as they are still superior to the slower lens you would use instead.  And you don't multiply by the same number as you would for focal length.

Tony Northrup has a very detailed video on F Stop and sensor size on YouTube.

Thanks for the prompt replies I do appreciate them.  It was Tony Northrup that set me off with this.  His theory is that as the focal length changes with the smaller sensors then the F number must change with the calculation that the F no is equal to the focal length divided by the aperture diameter but in my mind the physical length of the lens and the size of the aperture do not change then the F no must be as stated on the lens, hence my question to get other opinions on this point.  The other question this raises for me is that if a lens is made for a small sensor i.e. the Sony DT range why is the focal length not as stated as there is no cropping of the image on the sensor?


Hi  I am thinking about buying a Sigma wide angle lens for my nikon D 3200 .The two lens that interest me are the 10-20 f3.5 ex dc HSM and the 17-50 f2.8 ex dc os,taking in to account the crop factor which in the opinion of other members would be the best purchase ?    Many thanks MBS
Hi MBS,

I looked up the price of the Sigma 10-20 and at that price I would suggest that you consider the Tokina (Japanese made) AT-X 11-20 F2.8 Pro DX. That is one of the two items I have left to purchase to complete my camera equipment. The other is the 14E Teleconverter for my 200-500mm lens. I bought a Tokina 100mm Macro lens and use it as much for portraits as macro shots. Very solid lens and IMO sharper than any of the several Nikon lens I have. I am certainly going to buy the 11-20 next purchase.
 
Tokina Lens
Reply
#10
Sounds like a good idea. Stick RPG 2 I wanna buy the same one.
Reply
#11
I missed this thread first time around, I have the Sigma 10-20mm and love it. It's decently sharp, fairly fast focusing and doesn't vignette on my crop body. It is all but useless on my full frame though.
Reply

#12
I use tokina 11-16 f2.8 on crop body, it's insanely sharp wide open .A wider option would be sigma 8-16mm f/4.5-5.6 dc hsm which is very wide and rectilinear as well
Reply
#13
I have the f4 10-20 lens, very pleased with it, this is a bit off the subject but interesting. i had a Canon 40d converted to infrared with a 720nm filter put in, i tried the 10-20 on IR and it was rubbish, so i left it for a while, then a couple of months later i went out with the IR camera and when i got the camera out i was horrified, i still had the sigma on it. so i went ahead and spent the day taking shots but thinking i was wasting my time, but some of the best IR shots i have ever done were there, i had to make another set of actions to get the effects i wanted, and got some effects i did not bargain on, i was at park in October, one amazing effect i got was a shot of a tree and white bridge over a stream with almost natural range of colors, its half IR and half "normal" it seems it does not like the summer IR very smeared near the frame edges. lots to do to get used to these random effects.
Reply


Possibly Related Threads…
Thread Author Replies Views Last Post
  Distorted focal length sigma lenses. Madeelay 1 1,822 Oct 26, 2018, 03:06
Last Post: GrahamS
  Sigma Lens Repair EnglishBob 17 12,689 Oct 6, 2018, 04:55
Last Post: maisie
  Chromatic Lens Aberration WDHewson 6 2,926 Jan 13, 2018, 22:04
Last Post: EnglishBob

Forum Jump:


Users browsing this thread: 1 Guest(s)