September 16, 2014, 05:59:21 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - AlanF

Pages: [1] 2 3 ... 72
Site Information / Re: Noisy obtrusive ads
« on: September 15, 2014, 04:09:45 PM »
It's almost unthinkable that anyone this day and age would be using a browser without AdBlock and NoScript (I use them under Firefox).   The web is practically unusable without them, and quite dangerous.

Thanks - Adblock installed and it works.

Lenses / Re: What telephotos do we own?
« on: September 15, 2014, 04:03:54 PM »
How could you omit the 200-400 f4L IS 1.4x ??

Easy, but I have now added it.

Lenses / Re: Official: Canon EF 400mm f/4 DO IS II
« on: September 15, 2014, 10:30:15 AM »
It is a dramatic improvement, and they seem to have solved the contrast problem. However, it is now only 250g (1/2 lb) lighter than the 300mm f/2.8 II and so you pay your money and takes your choice between two outstanding lenses. I'd love to try the 400 DO. 800mm is very attractive with a 2xTC but we'll have to wait to find out what the AF is like at f/8.

Site Information / Re: Noisy obtrusive ads
« on: September 15, 2014, 10:20:53 AM »
Ads are a fact of life, but ones that start shouting at you without clicking a link to activate them are a step too far.

Lenses / Re: Official: Canon EF 400mm f/4 DO IS II
« on: September 15, 2014, 09:12:47 AM »
The price is £6,999 in UK - ouch! Here are the Canon MTFs of the 400 DO lined up against the 300 with TCs. Take care - Canon doesn't give them with diffraction included and the real f numbers are 1.4x and 2x higher with the TCs.

Site Information / Noisy obtrusive ads
« on: September 15, 2014, 07:32:18 AM »
Audio/video ads are being posted by Google that are activated simply by moving unintentionally the cursor over them without clicking. This activation happens when scrolling and the cursor slides over the ad. They are horribly noisy. Admin please get rid of them.

Lenses / What telephotos do we own?
« on: September 15, 2014, 07:20:46 AM »
With new telephotos being announced, questions asked about how many telephotos are sold, and the usual arguments about about which are better, it may be interesting to know the numbers and choices of CR members. To keep the options down, I haven't divided into I and II series.

EOS Bodies / Re: More Images of the Canon EOS 7D Mark II
« on: September 13, 2014, 02:43:19 PM »
This is not a troll attempt, i really would like to hear people's thoughts on the upcoming 7D Mark II when put up against the new Nikon D750. It seems the 7D Mark II will use an improved 70D sensor and the D750 uses an improved version of the D610 sensor. I realize this is an APS-C camera versus a Full Frame camera but the D750 has an APS crop mode that you can use which would mean you basically have two cameras in one. The DxOMark ratings for the D610 versus the 70D are drastically different with the D610 ranking a 94 and the 70D ranking at 68
- this disparity is bound to remain in the two new models given their base technologies as mentioned. Besides the obvious boost that the 7D Mark II will have over the D750 in terms of fps and the phase detect for video use, what other reasons are there for choosing the 7D Mark II over the full frame D750? The pricing will not be so different as the D750 is at $2,299 and the 7D MK II is expected to come in at ~$2K.

Thoughts anyone?

The crop mode of the 750 just uses the central 10 megapixels of the sensor and gives no extra reach over the FF - it just gives a narrower field of view. The 750 crop mode will give poorer resolution than the 20.2 mp of the 7DII or 70D and is a waste of time for bird photographers etc who use high mp crops to get some extra range.

Sigma UK has announced the price of the sports model (£15,999) and a launch date of Sept 2014, so perhaps the sceptics about release dates and vapour products might just be wrong.

Alan, I think you entered a extra digit in the price.  That price is up in Canon range. :)

I think this is what you meant.  Price: £1599.99

Good grief I just about had a heart attack!

Perhaps the lens is a Veblen (or positional) good whereby demand increases as price increases

Maybe Canon marketing has read the Wikipedia article?

Sigma UK has announced the price of the sports model (£15,999) and a launch date of Sept 2014, so perhaps the sceptics about release dates and vapour products might just be wrong.

The image Lee Jay posted is significantly better than either of those, just look at the clarity on the ridges.

Not that I could do any better, but the stacked TC's seem to do pretty well.

You have missed jrista's post - the clarity etc depends dramatically on conditions so you can't compare from one day to the next or from different locations. I posted these because they can be compared as they were taken at the same time. I also did one with the 100-400mm L on the 5DIII but without TCs. Here it is. If they were done in a less misty atmosphere they would be better.

The 100-400 + 2 x 1.4TCs doesn't look any better than the SX50, which costs less than 2 TCs

I hope you were kidding.  Your SX50 shot is noisy, over-sharpened, full of halos and artifacts, and full of CA.  Make sure you click on my shot to see it at full size.

Oops, I uploaded a version I was playing around with to increase contrast and vibrance. Here is the original, and one from the same night using the 300mm/2.8 + 2xTC on 5DIII for comparison (SX50 above, both through 1 round of DxO + 0.9 USM at 100%).

The 100-400 + 2 x 1.4TCs doesn't look any better than the SX50, which costs less than 2 TCs

Third Party Manufacturers / Re: SIGMA 150-600!!
« on: September 05, 2014, 09:59:14 AM »
It looks very good indeed from the MTFs. But, it is an absolute monster. It weighs 900g (2 lb) more than the Tamron and is significantly bigger.  It even weighs a couple of 100g more than the Canon 300/2.8 + 2xTC.

It's of little interest to me as if I need a smaller, lighter lens for travel the Tamron is more suitable, and if I want the best IQ I will use the Canon.  But, it could be a good choice vs the 300/2.8 +TCs if you can't afford the Canon and or  want a zoom. 

Really looking forward to the reviews.

This stuff just gets too technical for me, so let me ask a question.

I'm standing on the side of the road on a sunny day and I'm looking at a bald eagle that is 75 meters away sitting at the top of a tree.  In my camera bag is my 300mm 2.8 lens, a 7D and 5D3.

I'm shooting handheld.  I don't dare move closer for fear that I scare him off.

If I'm trying to produce a final/edited image that "fills the frame" with as much detail, sharpness, and overall IQ as possible, which body do I attach to the 300mm?

A fully grown bald eagle is 1 m long. The size of the image on the sensor for a 300mm lens 75 m away is 4 mm. corresponding to 930 pixels on the 7D or 640 on the 5DIII. 300mm is too short for a decent image. I would use the 300 mm + 2xTC on either camera as 1860 px on the 7D or 1280 on the 5DIII would give an excellent image. You didn't have the 2xTC in your bag, I know but that is bad planning.

Alan - out of curiosity, what's the maths behind subject size, lens, distance, size on sensor please? I've always wanted to be able to calculate this.

Is it focal length/(distance/subject size) = size on sensor?

Thanks in advance.

Sorry I missed this question - I am busy in Paris. If the subject is a long distance from the lens then the image is very close to being the focal length away from the lens. So,

subject distance/focal length = subject size/image size.

Pages: [1] 2 3 ... 72