November 27, 2014, 08:01:16 PM

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Topics - AlanF

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Third Party Manufacturers / Sigma 150-600 Sport vs Tamron 150-600mm
« on: October 29, 2014, 06:58:27 PM »
Lenstip, bless them, have done the first review of the Sigma 150-600mm sport. The MTFs are very impressive, and beat the Tamron. But it is a monster, heavier than the Canon 300/2.8 II + 2xTC. It weighs 2860g vs 1951 of Tamron. It is 120 x 290.2mm vs 105.6 x 257.8mm. (The 300/2.8 II is 128 x 248mm, 2350g)

It's a better lens than the Tamron but it is too large and heavy for me as it would be easier to carry and pack the admittedly much more expensive 300/2.8. Nevertheless, a very impressive lens.

Reviews / SX60 HS
« on: October 15, 2014, 04:04:26 PM »
The first reviews are trickling out, e.g,

It handles better than the SX50, it is reported. The local shop had one in today, which gave me the chance of a few shots side-by-side with the SX50. The evf is a real improvement and seemed more responsive, but I was more interested in the IQ at 1365 on the SX60 vs 1200mm.

I used iso 320 and RAW. Unfortunately, DxO doesn't have a raw converter for the SX60 yet but the latest DPP for Powershot works. The SX60 was very noisy, much noisier than the SX50, and the SX50 gave better results.

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.

Here is a way of calculating the effective extra reach or resolving power of a crop body versus FF, which will amuse the geeks among us.

Measure the MTF of a lens on the crop (= MTFcrop) and the same lens on the FF (= MTFff). The ratio of the MTFs, MTFcrop/MTFff, gives the relative resolving power of the bodies with that lens. However, the crop body can be placed 1.6x further away to give the same field of view. Therefore, the true effective relative resolving power, R, is given by:

R = 1.6x MTFcrop/MTFff.

Photozone lists measured MTFs for a set of lenses on the 5DII and 50D. I calculated their ratios for the Canon 200mm f/2.8 II, 85mm f/1.2 II and 35mm f/2 at wide apertures below the DLA. MTFcrop/MTFff is very close to 0.726 in all cases.

This gives R for 50D/5DII = 1.16.

So the effective extra reach is 16%.  (Based on the ratio of their pixel sizes, a value of 36% is expected.

The dpreview widget gives values for the 5DIII and 7D only for a few lenses. I did the same calculations with the Tamron 150-600mm (between 150-400mm), the Canon 200-400mm and the Sigma 50mm f/1.4 A at wider apertures below the DLA. In all cases, MTFcrop/MTFff is close to 0.742.

This gives R for 7D/5DIII = 1.19.

So, the effective extra reach is 19%. (Based on the ratio of their pixel sizes, a value of 45% is expected).

There are always arguments about using MTFs quantitatively, but I think in this particular calculation it is reasonably valid to use them. It fits in reasonably well with experience - Jon has shown there is better resolving power in photos of the moon with the 7D, but it doesn't look 45% better. And my own experience is that the 7D and 70D aren't much better than the 5DIII, certainly not 1.6x.

Animal Kingdom / Tamron 150-600mm bird pics
« on: August 19, 2014, 07:47:15 PM »
I have been on holiday in Canada for two weeks, walking with my Tamron 150-600mm and 5DIII. The birds are difficult to find - you suddenly come across small birds who will be around for a few seconds or minutes and then disappear. To get any photos you need a portable, reasonably long lens that you can swing into action in seconds. The birds are often hiding in bushes and you need IS for long exposures. My 300mm f/2.8 II + 2xTC III would have been the best solution, but the Tamron 150-600mm was more than good enough and more suitable for a holiday combining a family visit with the odd day for birding. Those knockers who have dismissed the Tamron in favour of a 400mm f/5.6L + 1.4xTC would have been completely stranded without IS - one of the exposures was as low as 1/50s and many in the 1/250 range. The 100-400mm would have been too short. The exifs are on the photos, which are all 100% crops, ie 1 pixel on the image = 1 pixel on the uncropped full frame. I was pleased with the haul. Most of the photos were in the Hammonds Plain area of Halifax NS.
The first 4: Canada Warbler 1/50s, Cedar waxwing, Black-capped chickadee, Ovenbird.

Please post images of your own from the 150-600mm Tammy.

Finally packing to go to Boston then Halifax next week. I was given helpful advice of places for bird photography and nature in

Any updates, more help and advice of where to go would be much appreciated.

I don't know whether to take my 300mm f/2.8 II plus extenders or settle on the Tamron 150-600mm for lightness and versatility at the expense of IQ at 600mm. What a terrible dilemma!

Photography Technique / Tour de France crops
« on: July 08, 2014, 10:11:24 AM »
Yesterday afternoon a stage of the Tour de France started from Cambridge, and I wanted a record of the parade coming out in front of my college, the tall Gothic building with the spire. So, I hung out of a 2nd floor window, with my right leg wedged between the wall and an armchair, on which my wife was instructed to sit and not get up. I used the 5DIII with a 70-200mm f/4 L IS at f/8 to increase the DoF and iso640 for a decent shutter speed. All images are reduced to fit.

I would like advice on the composition. Top is the uncropped image. Below a narrow crop to remove the spectators just below me and the wall of the building, and reduce the foreground. However, the Gothic building is rather to the right. Next is a squarer crop, which has some wall and faces, but the Gothic building is exactly 1/3rd way in. I like this version, despite the faces on the right. Bottom, is just to show the yellow and green jersyes as they went past (the 70-200mm is just so sharp).

Advice please on the best crop or left alone, bearing in mind the Gothic building is important?

Lenses / Fungus common on 500mm L IS?
« on: June 11, 2014, 04:42:24 PM »
I could not help but notice and wonder about a 500mm being listed on eBay UK: "First of all please note that there is fungal growth within the elements which is quite common with Canon 500mm lenses." Is it really true that fungus makes a bee line for a 500?

I have been taking some bird photos with the 300mm f2.8 + 2xTC on 5DIII where I have had to hold the kit at about 45 deg. The 4 kg or so gets a bit tiring after a while and so I have just ordered a Manfrotto carbon fibre monopod. It's a very good deal and a 234RC tilt head is thrown in for free. The stated load bearing for the head is 2.5 kg. I can see that if you clamp the base of the head to a rigid support and then tighten the head so that the camera is held rigidly then the maximum load bearing is crucial. It seems to me, however, that if all I am doing is to hold the camera and just use the tilt head as a loose hinge on a support and don't tighten it, then it should easily cope with the 4 kg as I am sharing the load and I am not putting stress on the bearings.  Does anyone have experience of 'overloading' the 234RC in this way?

Street & City / Is this you in the Shanghai smogscape?
« on: March 30, 2014, 08:32:51 AM »
Wandering around Shanghai's Pearl Tower with an Ixus 310HS in hand, I couldn't resist taking this shot of a Canon-lover posing posing for a Nikon.

You can see on the left how the distant buildings are lost in smog. This was a sunny day. It is so sad that Shanghai has this year succumbed to severe pollution. There follow a shot in mid-afternoon from the Pearl Tower over the smog-shrouded city, and another of relatively close buildings lost in the smog.

(All taken on the little Ixus 310HS I bought as a foolproof point and shoot for my wife last week - sold dirt cheap from the local dealer clearing out old stock. The little Canons are just so good).

Software & Accessories / LP-E6 third party and Canon Chargers
« on: March 19, 2014, 07:25:56 PM »
One of my LP-E6 batteries comes up with an error message that it communicates irregularly with my 5DIii but it still works fine. It charges correctly on my old charger supplied with the 5DIII a year ago. Today, I tried to charge it with the more recent apparently identical charger supplied with the 70D.  It doesn't charge but the charger goes into a rapid red flashing mode.   It looks as if Canon has nobbled it's more recent chargers so as not to work with some 3rd party LP-E6s, and my LP-E6 is not recognised as Canon.

We have an interesting thread of who would prefer a 600mm f/4 II versus 200-400mm f/4. Let's get down to the nitty gritty of who has actually bought or is in the process of buying one or more of the lenses discussed in the thread.

Lenses / lenstip beware!
« on: February 13, 2014, 12:56:34 PM »
I was directed to lenstip via google link and got this warning. Oh dear - I have visited several times directly.

Unpacked my Tamron this morning. Basically, it handled just as predicted by the lensrental data and the other good data published. It focussed fast at 400mm and below, and a bit sluggish at 600 on both a 5DIII and 70D. The IQ performance at 400mm and below was at about the same as the 100-400L, which I have sold.

Now for the test that I have wanted to see: how does it compare at 600mm vs the 300mm f/2.8 II plus 2xTCIII. I AFMAd it on a 5DIII and took a couple of shots of an iso 12233 chart. The chart was illuminated by only a halogen lamp. Images from both lenses were treated the same way for processing from raw. The Tamron was set for f/6.3 at 1/400s iso 2500, and the 300x2 at f/5.6 at 1/500. For the pair in the next post, both were at f/8 and 1/250. These are 100% crops, which need downloading for comparison.

Here are the Tammy at/f6.3 (Top) and the Canon at f/5.6 (Bottom)

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