April 16, 2014, 09:08:56 PM

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Messages - AlanF

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1
Please define 100% crop again - poor memory! :-[

Jack
Hi Jack
100% crop means that you have cut a section from the full frame and haven't reduced it in size.  So, 1 pixel in the crop = 1 pixel from the original. 
Always good to correspond with you.
Alan

2
Most lenses give great results with the image filling the frame. You see what a lens can do by looking at 100% crops of a small bird occupying just a small part of the frame, just like in the last posts. Here are three 100% crops I took with my 2.8 300mm II + 2xTCIII last weekend, with just a few hundred pixels each way occupied. I posted a few more today in the BIF thread. It is a great combo (and a nice back up for my Tamron 150-600).

3
I occasionally see raptors flying high, usually too high for photos. I took the kestrel (middle) and buzzard (bottom) last weekend and the marsh harrier (top) last December. They are all 100% crops, with the birds occupying only 400-500x600-700 pixels, which gives an idea of how far away they were. All are hand-held using the 5DIII + f/2.8 300mm II + 2x TC III at f/5.6. 600mm and iso 640. (I saw them while walking around and could not have used a tripod).


4
Lenses / Re: Lens Paint
« on: April 11, 2014, 02:48:53 PM »
Did not try it, but a short search on eBay brought "Touch up paint for Canon Lenses - "L" Series Ultrasonic Versions" http://www.ebay.com/itm/Touch-up-paint-for-Canon-Lenses-L-Series-Ultrasonic-Versions-/190846327452?pt=LH_DefaultDomain_0&hash=item2c6f53da9c state that the paint fits the 300mm.
Also has Canon black.


The paint is a match for the older lenses and not for the 300/2.8 series II that the OP has.

5
The front element of the 50/1.8 is set well back from the front of the mount and is well protected without the need for a filter.  I do protect expensive lenses that have the front element flush with the mount, but that is just a personal foible.  There is absolutely no need for a uv filter with the 50mm.
Just to make it clear: If you want a filter to protect the front element of a lens, it doesn't have to be an UV filter. A clear filter works just fine. UV filters are sometimes easier to find, that's why they are also used for lenses on digital cameras.
The protection mentioned here is protection from mechanical impact and/or moisture. There is no need to protect lens or sensor from UV light. For a $120 dollar lens it is in my opinion overkill.
UV protection for your skin however is recommended :)

Agree on all accounts. I bought a Marumi clear filter for my Tamron 150-600 a couple of weeks ago as I was intending to use the lens occasionally without its lens hood in crowded areas and because of reports in another thread that the front element did not look sealed. I am pretty impressed with it. It doesn't appear to have have affected picture quality, and I dropped it onto concrete and it survived without even a mark on the ring!

6
The front element of the 50/1.8 is set well back from the front of the mount and is well protected without the need for a filter.  I do protect expensive lenses that have the front element flush with the mount, but that is just a personal foible.  There is absolutely no need for a uv filter with the 50mm.

7
Lenses / Re: Philosophical question about Sigma Lenses - Why?
« on: April 05, 2014, 08:26:44 AM »

And again, it says Sigma started as a camera company, in the film days, 1961.  This is just off the top of my head, but Post World War II Japan saw the influx of capitalism and free markets...the profit motive.  Before this their markets were centered around pleasing their emperor, and his desire was to conquer the Pacific Rim countries.  So it was an economy based on building the machines of war, since the early 20th century.  America didn't like this, so we fought them...and they gave us a good excuse when they drew first blood attacking Pearl Harbor.  Sigma's founders loved cameras and photography, so that was their motivation.  I suspect that after a few years, they realized they couldn't compete with Canon and Nikon, so the focus turned more to just lenses (this likely became their primary focus by the late 1980's, if not before).  As for their "foveon" sensor, it was designed by an American in California named "Merrill" in the late 1990's, hence they later named a recent generation of their cameras "Merrill".


Thanks! I think that's the background story I've been looking for.

Quote
Those are different types of photography, but very likely what most other posters will suggest, is that you just buy the Canon 100L, and forget ever even trying Sigma lenses.


I don't rule anything out and Sigma will be welcome in my Camera bag in the near future.


Well, that is good, glad I could help...I've not seen your posts before today, so I welcome you to the forum!


According to Sigma's own official history, they started to produce their first lenses in 1961 but didn't produce their first SLR until 1976.

http://www.sigmauser.co.uk/index.php?option=com_content&view=article&id=51&Itemid=67

8
Lenses / Re: Canon 400mm DO
« on: April 02, 2014, 02:10:31 AM »
Carl
What do you think of the 400 DO outresolving a 600 f/4 L?
Alan

9
Lenses / Re: Canon 400mm DO
« on: April 01, 2014, 09:54:05 AM »
You wrote:
"For all the pomp about the 300 f/2.8 ii, once you slap on that 1.4x iii converter, it's not a vast improvement in sharpness, if any, over the bare 400 f/4 DO...from looking at Bryan's test comparison at the-digital-picture.com."

All I have said was what you wrote does not match up with Canon's own measurements and a simple examination of Bryan's site. I am not defending anything or have any of the motives that you somehow have attributed to me. Could we please restrict this to rational discussion.

10
Lenses / Re: Canon 400mm DO
« on: April 01, 2014, 06:04:29 AM »
Canon's own MTF charts show the 300mm f/2.8 II + 1.4xTC III (bottom) to be significantly better than the 400 DO (Top).
ps
Just checked Bryan's TDP comparison: the 300 at 420mm is distinctly sharper

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=338&Camera=453&Sample=0&FLI=0&API=0&LensComp=739&CameraComp=453&SampleComp=0&FLIComp=1&APIComp=0


Well, I did too, and it's not "distinctly sharper" except in the extreme full frame corners.  I would say "somewhat noticeable" on the full frame borders, and "not much different in the center".


What about Canon's own MTFs? Have they got it wrong showing the distinct superiority of the 300 @ 420mm?

11
Lenses / Re: Canon 400mm DO
« on: March 30, 2014, 10:01:19 PM »
Most telephoto lenses give stunning results if you can fill the frame with the subject. The differences show up when the subjects fill just a small portion of the frame - the better the lens the smaller the image that can be used. To show what a lens is really capable of, you need to show the whole frame, a 100% crop of the image to illustrate the detail, the aperture, ISO, camera, shutter speed etc.

12
Lenses / Re: Philosophical question about Sigma Lenses - Why?
« on: March 30, 2014, 09:51:15 PM »
Sigma started off as a lens company and started making cameras as a sideline.  It makes its cash from lenses.
Fuji started as by making film, went into making cameras as a sideline before the advent of digital, which saved them as they were pre-adapted to digital.

What would happen if Canon started producing their lenses with other mounts? Well, there would be lots of happy Sony bunnies and maybe some Nikons. But, Canon might lose more of its profitable sales of bodies that rapidly become obsolete than it gains from long-lived glass. Canon has most certainly done the calculations and will stick to Canon-only lenses. 

13
Lenses / Re: Canon 400mm DO
« on: March 30, 2014, 10:25:54 AM »
The Tamron 150-600mm is the same weight as the 400 DO, costs less than 1/5th of the price, has much better IS, and you will have a shock when you compare them at 400mm:

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=338&Camera=453&Sample=0&FLI=0&API=0&LensComp=929&CameraComp=453&SampleComp=0&FLIComp=3&APIComp=0

14
Lenses / Re: Canon 400mm DO
« on: March 30, 2014, 09:30:30 AM »
Canon's own MTF charts show the 300mm f/2.8 II + 1.4xTC III (bottom) to be significantly better than the 400 DO (Top).
ps
Just checked Bryan's TDP comparison: the 300 at 420mm is distinctly sharper

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=338&Camera=453&Sample=0&FLI=0&API=0&LensComp=739&CameraComp=453&SampleComp=0&FLIComp=1&APIComp=0

15
Don
You are so right about turning on the self-timer by mistake. The SX50 is a fantastic little camera (I set up thread showing how it could for static photos out-resolve a 100-400 on a 5DIII). But, my wife turns on the self-timer every time so I have just bought her a touch-screen driven Ixus, which is basically foolproof. The little Ixus 310HS performs very well and I have just posted some photos in the City and Street scenes section.

The most important improvement would be to speed up the AF by using dual pixel technology.

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