SteB

SteB

Lives in United Kingdom North Shropshire, United Kingdom
Joined on Apr 3, 2007

Comments

Total: 123, showing: 1 – 20
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In reply to:

SteB: As I've tried to explain on the forum, this is very uniform distribution, which is the opposite of random distribution.
http://en.wikipedia.org/wiki/Randomness

If this was just random dust it would not be distributed like this. It could be dust trapped in the sandwich covering the sensor, but there would have to be something in the manufacturing process causing it to be evenly distributed. This is why I'm guessing a fault in the manufacturing process, for it to cause this uniform distribution.

Anyone who has studied distribution, randomness, statistics and probability in depth, will be aware that it is very unlikely that such a uniform distribution like this would be caused by a random fault like dust falling onto something. It could be dust again, but it would be dust formed by part of a process.

I'm fairly certain this will be fixed, once they discover what part of the manufacturing process is causing it.

@Rishi Sanyal - no problems, I accept it as ironic. Don't worry, I'm a fully fledged nerd. It's just that often when I get called one, it ain't a compliment.

All the best.

Direct link | Posted on May 22, 2015 at 22:00 UTC
In reply to:

SteB: As I've tried to explain on the forum, this is very uniform distribution, which is the opposite of random distribution.
http://en.wikipedia.org/wiki/Randomness

If this was just random dust it would not be distributed like this. It could be dust trapped in the sandwich covering the sensor, but there would have to be something in the manufacturing process causing it to be evenly distributed. This is why I'm guessing a fault in the manufacturing process, for it to cause this uniform distribution.

Anyone who has studied distribution, randomness, statistics and probability in depth, will be aware that it is very unlikely that such a uniform distribution like this would be caused by a random fault like dust falling onto something. It could be dust again, but it would be dust formed by part of a process.

I'm fairly certain this will be fixed, once they discover what part of the manufacturing process is causing it.

@Rishi Sanyal

That's why I hope the "nerd" jibe wasn't directed at me. If it was, it was extremely unprofessional, and not very clever.

I was making a serious point i.e. that this was a likely systematic fault in the manufacturing process, and not just random dust getting trapped between the layers as was first hypothesized when Roger Cicala of Lens Rentals first revealed the problem.

You will note on this sub-thread, I said without knowing much about the manufacturing process, that the "sputter deposition" process fault, was a far more likely hypothesis than the other suggestions.

I have a deep understanding of using Occam's Razor and probability, which is why I'm not often wrong. I was trying to aid understanding of this problem. Because if it was a systematic manufacturing process fault, it would likely effect a large proportion of the batch manufactured, when this fault was occurring. It seems hindsight has proven me right.

Direct link | Posted on May 22, 2015 at 08:58 UTC
On Canon issues product advisory for Rebel T6i/T6s article (139 comments in total)

Good response from Canon. As I point out earlier it would be a problem for high magnification macro photographs taken at small apertures. The slightest bit of sensor debris shows up and it would have been a nightmare having to spot that lot out on every image. As long as the effected cameras are identified, and there is a solution, it's fine. I was slightly worried by the explanation that it wouldn't be a problem with normal photography. However, as long as there's a free fix and the effected cameras are identified it's fixed as far as I'm concerned.

Direct link | Posted on May 9, 2015 at 09:42 UTC as 12th comment
On Metz mecablitz 26 AF-1 Quick Review article (69 comments in total)

I think this little flashgun has a lot of potential for use as a macro flash, especially with small none extending macro lenses on mirrorless cams. The position is just right, and it would be possible to make simple diffusers that gave great light. It would work well with my original cup diffuser, or variants of it.

This type of diffuser can be made with various different materials, in different shapes, and it words as well with single flashes as it does with twin flashes.
https://flic.kr/p/6ykgQD

Direct link | Posted on May 7, 2015 at 13:50 UTC as 30th comment
In reply to:

SteB: As I've tried to explain on the forum, this is very uniform distribution, which is the opposite of random distribution.
http://en.wikipedia.org/wiki/Randomness

If this was just random dust it would not be distributed like this. It could be dust trapped in the sandwich covering the sensor, but there would have to be something in the manufacturing process causing it to be evenly distributed. This is why I'm guessing a fault in the manufacturing process, for it to cause this uniform distribution.

Anyone who has studied distribution, randomness, statistics and probability in depth, will be aware that it is very unlikely that such a uniform distribution like this would be caused by a random fault like dust falling onto something. It could be dust again, but it would be dust formed by part of a process.

I'm fairly certain this will be fixed, once they discover what part of the manufacturing process is causing it.

"As I said below, my guess is a defective sputtering process for applying a coating. What do I win if I'm right? ;-)"
That sounds very plausible to me. It's basically what I was saying, that it was a systematic manufacturing fault. In other words it was not the random dust suggested in response to the LensRentals article.

I don't know enough about the manufacturing process to know what it likely is. However, your explanation sounds very plausible. Far more plausible than it was random dust trapped between layers.

Direct link | Posted on May 1, 2015 at 11:45 UTC
In reply to:

SteB: As I've tried to explain on the forum, this is very uniform distribution, which is the opposite of random distribution.
http://en.wikipedia.org/wiki/Randomness

If this was just random dust it would not be distributed like this. It could be dust trapped in the sandwich covering the sensor, but there would have to be something in the manufacturing process causing it to be evenly distributed. This is why I'm guessing a fault in the manufacturing process, for it to cause this uniform distribution.

Anyone who has studied distribution, randomness, statistics and probability in depth, will be aware that it is very unlikely that such a uniform distribution like this would be caused by a random fault like dust falling onto something. It could be dust again, but it would be dust formed by part of a process.

I'm fairly certain this will be fixed, once they discover what part of the manufacturing process is causing it.

"You can produce random numbers with uniform distribution.

Having a uniform or any other distribution does not mean it is not Random (exactly reverse, it means it is random with uniform distribution). You can of course have random with Normal, Poisson and other distributions too."

It is possible but unlikely. With the stochastic process of dust simply falling onto a material, this uniform distribution, would be unlikely.
http://en.wikipedia.org/wiki/Stochastic_process

In simple terms, with the volume of spots, it most likely to be due to a systematic process, and not merely dust falling randomly onto a material. However, manufacturing processes can of course distribute dust in a systematic, and none random way.

In a nutshell, normal sensor dust isn't like this in distribution. However, the mirror and shutter mechanism, do mean that sensor debris is more likely to accumulate in some positions than others. I realise this isn't normal sensor dust, and it's an analogy.

Direct link | Posted on May 1, 2015 at 08:40 UTC

As I've tried to explain on the forum, this is very uniform distribution, which is the opposite of random distribution.
http://en.wikipedia.org/wiki/Randomness

If this was just random dust it would not be distributed like this. It could be dust trapped in the sandwich covering the sensor, but there would have to be something in the manufacturing process causing it to be evenly distributed. This is why I'm guessing a fault in the manufacturing process, for it to cause this uniform distribution.

Anyone who has studied distribution, randomness, statistics and probability in depth, will be aware that it is very unlikely that such a uniform distribution like this would be caused by a random fault like dust falling onto something. It could be dust again, but it would be dust formed by part of a process.

I'm fairly certain this will be fixed, once they discover what part of the manufacturing process is causing it.

Direct link | Posted on May 1, 2015 at 07:28 UTC as 98th comment | 14 replies

This is just a general interest question, and no attempt to put the camera down. To me cameras are just tools, each having pros and cons.

My question is does Pentax use Electronic First Curtain (EFC) shutter yet, in this or any other Pentax camera?

Direct link | Posted on Apr 23, 2015 at 18:51 UTC as 9th comment | 3 replies
In reply to:

talmy: If it isn't *amazingly* good it won't stand a chance at that price. I'd call this one a disappointment after some of the other Samyang lenses.

Yes, I'm saying that when composing at high speed with active subjects, it is advantageous to use the thinner DOF wide open as a guide.
https://www.flickr.com/photos/9578475@N02/

Often you have very little time, sometimes less than a second, to select a certain type of pose or composition, with a feeding insect, and then the opportunity is lost. Of course in other scenarios you don't need to select the composition, pose or focus so rapidly, but absolute precision is important. If the focus is just a fraction out the photo doesn't work as well.

Whilst the DOF is obviously greater at the taking aperture, say f11, once you are at life-size or above, the DOF is still razor thin at any aperture, just less thin. I've shot with manual stop down lenses on a DSLR, and it is much harder to judge exactly where the focus plane is at the taking aperture. Often I use a sort of zone focus approach, guessing where the true plane of focus is from experience.

Direct link | Posted on Apr 3, 2015 at 12:03 UTC
In reply to:

talmy: If it isn't *amazingly* good it won't stand a chance at that price. I'd call this one a disappointment after some of the other Samyang lenses.

Auto-stop down is important in macro for 2 main reasons. It is most important when shooting handheld, which will often be with flash, which with full flash, is used to freeze motion.

DSLR viewfinders become dark at smaller typical macro apertures. Plus at 1:1, the effective aperture will be about 2 stops smaller than the indicated nominal aperture.

Also the placement of focus is absolutely crucial for a successful macro image. Not just the point of focus, but the angle of the plane of focus, for maximal coverage of the subject. It's a lot easier to judge where the precise plane of focus is when the lens is wide open.

However, focus peaking as in the EVF or LCD of a mirrorless cam, can be a very useful focusing aid. A lot of macro photography success is about learning where to place to precise pointof focus, and the angle of the plane of focus.

Direct link | Posted on Apr 3, 2015 at 10:35 UTC
In reply to:

SteB: I'm puzzled at who this lens will appeal to, and what was the thinking of Samyang in creating it. I can see some interest in the VDSLR version, as auto stop down has no advantages with video.

Macro lenses are generally good performers, and there's some very good lenses in this class from Tamron, Sigma and Tokina. These lenses have auto stop down, and AF, which is not as important on a macro lens as auto-stop down. No matter how good the Samyang is optically, it is not going to clearly outperform the others. Generally for single exposure macro photographs the aperture used is well into the diffraction limited zone, and this tends to flatten out any minor IQ differences between lenses. Most macro lenses are already that good that you have to do serious pixel peeping to detect differences in performance.

Usually Samyang lenses have a USP such as price, performance, or maximum aperture, which makes them an attractive option over other choices, but not this one.

"Most macro shooters who really practice it, don't use AF."

Yes, I'm one of them.
https://www.flickr.com/photos/9578475@N02/

I very rarely use AF for macro. However, I am not saying it has not use, simply that manual focus is preferable. Personally I tend to set the magnification, and physically move backwards or forards to get precise focus.

You will notice I highlighted the importance of auto stop down of the aperture, and not AF. This most definitely is useful in macro photography.

Direct link | Posted on Apr 3, 2015 at 10:27 UTC
In reply to:

talmy: If it isn't *amazingly* good it won't stand a chance at that price. I'd call this one a disappointment after some of the other Samyang lenses.

You're right. The whole problem though, is that the reasonably priced competitors are already superb performers, lighter, have AF, and far more importantly, auto-stop down. Even if this was one of the very best performing macro lenses ever produced, it would still only be a niche product.

Direct link | Posted on Apr 2, 2015 at 22:44 UTC
In reply to:

SteB: I'm puzzled at who this lens will appeal to, and what was the thinking of Samyang in creating it. I can see some interest in the VDSLR version, as auto stop down has no advantages with video.

Macro lenses are generally good performers, and there's some very good lenses in this class from Tamron, Sigma and Tokina. These lenses have auto stop down, and AF, which is not as important on a macro lens as auto-stop down. No matter how good the Samyang is optically, it is not going to clearly outperform the others. Generally for single exposure macro photographs the aperture used is well into the diffraction limited zone, and this tends to flatten out any minor IQ differences between lenses. Most macro lenses are already that good that you have to do serious pixel peeping to detect differences in performance.

Usually Samyang lenses have a USP such as price, performance, or maximum aperture, which makes them an attractive option over other choices, but not this one.

Samyang could have created a macro lens, which would have been attractive to macro photographers. However, if it was a 100mm lens, the most crowded sector of the market, it needed something else to make an manual aperture lens like this attractive. It needed greater that 1:1 focusing and/or a tripod collar.

I'm baffled at how little manufacturers understand the need of macro photographers.

Samyang would have created great interest from macro photographers with a 150mm-200mm+ macro lens, or a shorter focal length which went to 2:1 or greater.

Direct link | Posted on Apr 2, 2015 at 22:36 UTC

I'm puzzled at who this lens will appeal to, and what was the thinking of Samyang in creating it. I can see some interest in the VDSLR version, as auto stop down has no advantages with video.

Macro lenses are generally good performers, and there's some very good lenses in this class from Tamron, Sigma and Tokina. These lenses have auto stop down, and AF, which is not as important on a macro lens as auto-stop down. No matter how good the Samyang is optically, it is not going to clearly outperform the others. Generally for single exposure macro photographs the aperture used is well into the diffraction limited zone, and this tends to flatten out any minor IQ differences between lenses. Most macro lenses are already that good that you have to do serious pixel peeping to detect differences in performance.

Usually Samyang lenses have a USP such as price, performance, or maximum aperture, which makes them an attractive option over other choices, but not this one.

Direct link | Posted on Apr 2, 2015 at 22:27 UTC as 39th comment | 3 replies
In reply to:

goblin: Yooo :D :D :D

I recognize these chops ! This is the guy who declared five or six years ago that "Two years from now Olympus will no longer build dslrs, only mirorless cameras", starting a bushfire and prompting official denials from Olympus :)

Listen carefully to everything will happen within the next couple of years, it will happen in the next six :)

You're right. What he actually said is that within a years no Olympus would have an optical viewfinder, because they had an amazing EVF. He got slaughtered for it. But essentially he had told people about the E-M1 before the E-M5 had been released. So it's worth listening to what he says.

Direct link | Posted on Mar 11, 2015 at 23:29 UTC

I've been looking around to find more information about this head. The only review I could find is this hands on Thai review. With Google translate some of it is understandable, but as usual there are some eccentric translations of phrases. Best of all there are actual photos, and a photo with it alongside the 410 - although this is lower down and slightly further back. I'd say there are similar dimensions, and interestingly the knobs look about the same diameter. The review seems to say the adjustments are easier and smoother. I think the photos are more useful for gaining an impression, that the Manfrotto product photos.
http://www.2how.com/review/manfrotto-gear-head/

The UK price on the Manfrotto site is quite a bit less than the 410 on there, but more than the average street price of the 410. In other words after it has been on sale for a while, it should be cheaper than the 410.

Direct link | Posted on Mar 9, 2015 at 01:00 UTC as 3rd comment
In reply to:

NancyP: I think that there is a market for a geared head that is lighter than the 410, for the users of mirrorless cameras. I have to say that my tiny Sigma DP2M (8 oz) looks a little silly on top of the Manfrotto 410/Hejnar adapter plus Manfrotto 055 legs.The only geared heads out there are Manfrotto, Arca-Swiss Cube and D series, and the Sunwayfoto knockoff of the Arca D4 (not available in US).

Hi bedbug

I have wondered about the durability myself. Although I think it's a double edged sword. The polymer construction might be better at shock abortion. A lot of people use carbon fibre or wooden tripods. But the shock is transmitted to the tripod via a diecast alloy head.

I've been looking at a lighter geared head. I find even the 410 makes a tripod top heavy for carrying around. Often I end up lugging one around just in case, and hardly use it at times. Yet when I take a lighter ball head out just in case, Murphy's law says I find something interesting, and composing with a ball head at greater than life size always makes you miss a geared head.

This is a lot cheaper than the Swiss Arca D4 or the Sunwayfoto knock of I was looking at, plus I'll hang on to the 410. So it's come just at the right time for me.

Direct link | Posted on Mar 6, 2015 at 12:49 UTC

Personally I don't find the 200PL QR too limiting because I usually use a focusing rail with a geared head for field macros. So the lens attachment is still something you have a choice over.

My personal bugbear about this new head is that whilst being much lighter than the 410, which I've been using for quite some time now, it isn't any more compact.

Direct link | Posted on Mar 5, 2015 at 15:03 UTC as 8th comment
In reply to:

luben solev: At last. This is the first new geared head to come out in over 10 years. I love using my Manfrotto 410 Junior Geared Head, so it's good to see this niche line of heads continue being developed. Shame none of them come with a QR with as good a quality as RRS etc.

Same here. However, I'm not too bothered as I usually use a focusing rail with the geared head so my choice of QR is really what's on top of the focusing rail.

Direct link | Posted on Mar 5, 2015 at 14:56 UTC

It seems very interesting. Although as others have noted it's not particularly heavy duty as the write up claims. It has the lightest load weight of all the Manfrotto geared heads. I've been using a Manfrotto 410 geared head for macro for quite a few years, and it's very good except for the weight. This weight reduction will be welcome. The other thing is I don't like the quick release plate on 410 and normally use a 200PL adapter on it. It's a polymer body though. Although I suppose it could have advantages when it comes to vibration dampening.

Direct link | Posted on Mar 4, 2015 at 23:06 UTC as 24th comment
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