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Messages - AlanF

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136
Lenses / Re: Stacked TCs - 1.4x III + 12mm Extension Tube + 2x III
« on: June 30, 2014, 12:27:02 PM »
What does sharpness being reduced 50% mean? Does that mean with 2x+1.4x relative to bare lens? Since adding a 2xTC can increase resolution by a maximum of x2 and a 1.4xTC by a maximum of x1.4, it doesn't look as if you are gaining anything by stacking them.

You've got a point. But remember the 2x extender increases the pixels on target by 4x. 2x in two dimensions, if that makes sense (so, say the bare lens gave you a subject 1000x1000 pixels, that would be 1MP; doubling the focal length gives you 2000x2000, which is 4MP).

It has a couple of advantages I would say. First, it makes the subject bigger in the viewfinder, which can help if you're focusing manually. Second, if you were to crop to the same size the noise patterns would be different. again it's hard to put into words. But shrinking down an image taken with a longer focal length would reduce the appearance of noise, whereas simply cropping to give the same field of view at a shorter focal length makes the noise more apparent.

In my subjective view, 2x + 1.4x does give extra resolution. Beyond that, you're not gaining any extra details, but the above points hold (the big exception being stacked astrophotography, where you regain all that resolution by combining multiple images, so any extra focal length is good).

In terms of number of pixels, sure doubling f means you get 4x more on target. However, if you halve the the resolution in 1 dimension you lose 2x2 = 4x in two dimensions. So, you have got nowhere. Now mackguyver has just found that adding the 1.4 to the 2x lowers the sharpness from 80 to 50%, ie by a factor of 1.6, for an increase in f of 1.4x. So you have actually moved back in resolution for a loss of autofocus and aperture.

137
I get my share of very sharp close ups, seeing the barbs on the feathers, the rings around the eyes etc. But, it is just as much fun catching a scene at low resolution. On Saturday I went for a walk with my son and grandson and saw for the first time fledgeling barn owls, which I have been trying to see for the past 5 years, but always missed them. Here they were and I was able to swing the 5DIII and 300mm/2.8 + 2 xTC into action hand held (iso640, 1/320, f/5.6). You can't get closer than about 50-60 metres, and you could barely make them out by eye. But, here is a nice memory, and my son immediately took it as a screen saver. Went back yesterday with my new monopod for assistance, but the birds were gone again.

Their faces occupy only 90x90 pixels. Without the 2xTC you would hardly resolve their eyes.

138
This shot taken with 300 ii +2xiii not cropped ,love how sharp compared to my 100-400 but did get some nice shot with that lens too

Not cropped! How did you get so close?

139
Lenses / Re: Stacked TCs - 1.4x III + 12mm Extension Tube + 2x III
« on: June 30, 2014, 06:41:51 AM »
I finally had a suitable subject to try the stacked extenders - in this order (1.4x III + 12mm Extension Tube + 2x III) and I had some trouble with focus because the tree the owl was on was moving, but I found with IS on, I was able to do a good job using the viewfinder.  It was too dark in the shade to use LiveView unfortunately, but I did use a cable release & tripod.  CA was minimal, but contrast was reduced around 25% and sharpness probably around 50%.  It's still a very usable image for anything 8x10 and smaller - here's the full photo, uncropped:



What does sharpness being reduced 50% mean? Does that mean with 2x+1.4x relative to bare lens? Since adding a 2xTC can increase resolution by a maximum of x2 and a 1.4xTC by a maximum of x1.4, it doesn't look as if you are gaining anything by stacking them.

140
Lenses / Re: Stacked TCs - 1.4x III + 12mm Extension Tube + 2x III
« on: June 30, 2014, 12:46:01 AM »
Was the order camera 1.4x III + 12mm Extension Tube + 2x III lens or lens 1.4x III + 12mm Extension Tube + 2x III camera?

141
These are beautiful images by all accounts.  I do see slight iq degradation, especially in looking at the fine details in the feathers and hairs of the animals, compared with what the 300 2.8 II can do alone.  I don't know how much of this is due to downgrading of the image to get posted. 

I would be proud to take these pics, don't get me wrong, but I really love when you can see every hair, or very fine feather quill and vein.

sek
You would lose even more fine details without the 2xTC. You have to get twice as near without the TC to resolve the same level of detail. I like also to capture every detail of feathers, but you have to get close enough to do so, and the 2xTC lets you do it at twice the distance. 

142
Lenses / Re: Any word on the 50mm with Image Stabilzation?
« on: June 29, 2014, 03:42:51 PM »
I have asked in the Review thread of the 35A whether people are still happy with the lens but with no reply. If other people are having problems with the 35A I'll give it a miss.

143
Software & Accessories / Re: DxO Optics Pro 9, Elite Edition
« on: June 29, 2014, 12:24:04 PM »
"export DxO as a jpeg and then open with PS"

Blasphemy!  If Thou intend to further edit in PS then Thou shalt export in a lossless format!  Be this the proclamation!

Your grammar is worse than blasphemous: Thou intendest, not Thou intend; to edit further, not to further edit (no split infinitives are to be found in the works of Shakespeare, Spenser, Pope, or Dryden, or in the King James Version of the Bible).

Fair enough  :P

Good sport! And I agree that for serious editing lossless is better, but I usually do minor stuff in PS.

144
Software & Accessories / Re: DxO Optics Pro 9, Elite Edition
« on: June 29, 2014, 11:16:27 AM »
"export DxO as a jpeg and then open with PS"

Blasphemy!  If Thou intend to further edit in PS then Thou shalt export in a lossless format!  Be this the proclamation!

Your grammar is worse than blasphemous: Thou intendest, not Thou intend; to edit further, not to further edit (no split infinitives are to be found in the works of Shakespeare, Spenser, Pope, or Dryden, or in the King James Version of the Bible).

145
Software & Accessories / Re: DxO Optics Pro 9, Elite Edition
« on: June 29, 2014, 10:25:55 AM »
Does DxO do anything special when it exports to LR? (I don't use LR so don't know what this is about). I just export DxO as a jpeg and then open with PS.

146
Software & Accessories / Re: Apple to Cease work on Aperture
« on: June 28, 2014, 03:08:17 PM »
DxO PRIME NR is truly remarkable.

147
Reviews / Re: Review - Sigma 35mm f/1.4 DG HSM
« on: June 27, 2014, 05:40:19 PM »
9 months further on, are people still happy with the Sigma 35mm? I am thinking of buying one. 

148
Software & Accessories / Re: Apple to Cease work on Aperture
« on: June 27, 2014, 03:12:15 PM »
One of the worse things about Apple is that they will dump software or facilities without caring about their customers. I once had Apple as an ISP, and it lasted about a year, iDisk, and they dropped it, a paid subscription to MobileMe for many years, and it was suddenly pulled.

149
Here are a few bird photos taken at random. 300mm /2.8 II + 2xTCIII on 5DIII. Usually f/5.6 and iso 640

150
Animal Kingdom / Re: Show your Bird Portraits
« on: June 23, 2014, 09:40:19 AM »
Harpy Eagle, Belize

How did you get that close?

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