Richard Butler

Richard Butler

Lives in United Kingdom Seattle, United Kingdom
Works as a Reviews Editor
Joined on Nov 7, 2007

Comments

Total: 2569, showing: 61 – 80
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On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

John McMillin: The best reason to buy a mirror less is to get a smaller and lighter camera. So doesn't it make sense to provide smaller and lighter lenses for it? That hardly seems worth arguing about. And bring on the f4 lenses, too. If they were useful in the days of !SO 200 films, they certainly have a use now. Recently I used a Minolta 70-210/4 Beercan with my a850 FF for a portrait shoot, and the results delighted me, and my customer. How fuzzy a background do you want, anyhow?

Where does this article compare 50-140mm F2.8s to 70-200mm F2.8s **on full frame**?

The only place full frame is referenced in the entire article is saying that 70-200mm F4s offer similar capabilities.

Direct link | Posted on Sep 23, 2014 at 19:49 UTC
In reply to:

mpgxsvcd: What makes the LX100 a "Point and Shoot" camera. Yes it has an Auto mode. However, all cameras including Full Frame DSLRs have an Auto mode.

The term "Point and Shoot" is what should die. There is no such thing as a point and shoot camera. All cameras have some sort of camera control now.

The more appropriate term is compact or more specifically you can say small sensor compact or large sensor compact.

I've adjusted the first page to try to make a clearer distinction between small-sensor, limited control 'point-and-shoots' and the larger-sensor enthusiast compacts that offer more control and better features.

Direct link | Posted on Sep 23, 2014 at 17:38 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

John McMillin: The best reason to buy a mirror less is to get a smaller and lighter camera. So doesn't it make sense to provide smaller and lighter lenses for it? That hardly seems worth arguing about. And bring on the f4 lenses, too. If they were useful in the days of !SO 200 films, they certainly have a use now. Recently I used a Minolta 70-210/4 Beercan with my a850 FF for a portrait shoot, and the results delighted me, and my customer. How fuzzy a background do you want, anyhow?

@EinsteinsGhost - the article doesn't compare 50-140mm F2.8 on APS-C to 70-200mm F2.8 on full frame, it compares them both on APS-C.

It then mentions that 70-200mm F4s on FF are the closest equivalents, but that you need to have a full frame camera.

Equivalence is only relevant when comparing across formats, so is only discussed in the two places where other formats (full frame and Micro Four Thirds) are referred to.

Direct link | Posted on Sep 23, 2014 at 17:25 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

shademaster: Hey, Sony. If you make an APS-C A-Mount 50-150 f/2.8 at 770g like the sigma, I'll buy it and an SLT.

Also: it is frustrating that all the long e-mount stuff is full frame. It would be nice to make an e-mount fast long zoom for aps-c that doesn't weight/cost a ton. I guess we'll all stick with samsung and fuji.

...and is a stop faster.

Direct link | Posted on Sep 23, 2014 at 17:18 UTC
On Canon PowerShot G7 X First Impressions Review preview (874 comments in total)
In reply to:

telefunk: Did it occur to anyone (reviewers included) that the sensor might be from the first generation RX100? Would make sense for Sony to sell old tech... But plenty good for my needs.

The first generation RX100 used an FSI CMOS sensor.

The RX100 II and III use a BSI sensor, as does the G7 X. Equally, it's the BSI version that Sony Semiconductor has publicised the specs of.

Direct link | Posted on Sep 23, 2014 at 00:55 UTC
In reply to:

rufusrm44: This statement is false:

"Quite simply, the smaller sensor will receive less light at matched exposures (same shutter speed and aperture) and this means more noise."

It's only true if the pixel pitch is lower (meaning the pixel density is greater.) But if the number and size of the pixels are identical, that less light received on the m43 sensor is equivalent to the 'more' light gathered by full frame because the full frame requires more light to cover the larger sensor.

Imagine if you had a sensor that was cut 1/4 the size of the full frame sensor. That means it only needs the same shutter speed and aperture to produce the same quality of image, but that image would be only 1/4 the pixels of the ff sensor, and would therefore only need 1/4 the light.

The error is in assuming you *need* more light for the larger sensor.

If you look at [the diagram at the top of this page](http://www.dpreview.com/articles/2666934640/what-is-equivalence-and-why-should-i-care/2), you'll see that you don't *need* more light, you *get access to* more light at any given f-number.

If you use the same lens on each sensor, then the larger sensor collects all the additional light around the edges.

If you use a wider lens on the small sensor to match the wider angle-of-view offered in the first diagram, then you'll use a shorter focal length and therefore the same f-number will be using a smaller aperture diagonal. Either way, the larger sensor gets more light (it's not the same amount of light averaged over a larger area).

Direct link | Posted on Sep 22, 2014 at 21:22 UTC
In reply to:

rufusrm44: This statement is false:

"Quite simply, the smaller sensor will receive less light at matched exposures (same shutter speed and aperture) and this means more noise."

It's only true if the pixel pitch is lower (meaning the pixel density is greater.) But if the number and size of the pixels are identical, that less light received on the m43 sensor is equivalent to the 'more' light gathered by full frame because the full frame requires more light to cover the larger sensor.

Imagine if you had a sensor that was cut 1/4 the size of the full frame sensor. That means it only needs the same shutter speed and aperture to produce the same quality of image, but that image would be only 1/4 the pixels of the ff sensor, and would therefore only need 1/4 the light.

@rufusrm44 - your response actually contains the answer (and an error):

A higher resolution gives the appearance of less noise. Exactly. Because there *is* less noise. If you blow it and the APS-C image up to the same size to view, it'll be less noisy, if you let your software resample them both to the same size on your monitor, it'll be less noisy.

And it works either way: if the smaller and larger sensor have the same pixel *count*, then the larger image will be cleaner. If they have the same pixel *size* then the larger image has more resolution, which means less noise at a common viewing size.

(Assuming similar sensor designs)

Direct link | Posted on Sep 22, 2014 at 21:10 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

vscd: You will *never* get the same picture on the Crop as with a 200mm @f2.8 on fullframe. Yes it's bigger gear... but why do you all scream for size? If you nail a pin you use a hammer, not a spoon.

@EinsteinsGhost - priorities are entirely in the mind of the individual making the decision or taking the photograph.

If your priority is greater reach, then a longer lens is going to be preferable.

Since I want to be able to use such a lens for portraiture as well as full-zoom telephoto work, a lighter lens with a range that was traditionally considered to be sufficient is preferable to something with a bit more reach that I've found too heavy to carry with me.

Direct link | Posted on Sep 22, 2014 at 18:01 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

supeyugin1: You also forgot Pentax Q 15-45/2.8, it's an equivalent of 69-207 on Pentax Q7. The weight is 90g/3.17oz and the length is 56mm. The quality is excellent, and the price is only $300. I've got it as a part of a bundle, so it's cost was $200 for me.

I didn't forget it, it's just that the Q system uses sensors so much smaller than APS-C that you don't get the same control over depth-of-field of the lenses I'm talking about, so I don't really consider it to achieve the same thing.

For instance I like these 50-150mm F2.8s for portraiture, where shallow depth-of-field is often thought to be desirable.

Not that I have anything against the 15-45mm, it just doesn't achieve the same things, so I haven't included it in this article.

Direct link | Posted on Sep 22, 2014 at 17:56 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

Just another Canon shooter: "I owned a 70-200mm lens for several years and rarely used it, because I couldn't face carrying it around.

However, a 50-150mm (in this case the first-generation, 770g unstabilized Sigma) was light enough that I had it with me and was able to quickly grab a shot when I bumped into the then National Circuit Race and World Track Team Pursuit champion."

The Canon 70-200/4 IS is 10g lighter.

@Just another Canon shooter - I didn't explain every single caveat of that statement because it's a picture caption, not a scientific paper.

In an article that is almost exclusively about APS-C, it's reasonable to assume I'm talking about APS-C.

Since both those shots were taken wider than F4, then a 70-200mm F4 would have been a poor substitute for the lens I used.

I make clear in the article that a 70-200mm F4 *on full frame* makes as much sense as these ~50-150mm F2.8s do on APS-C, but I don't *personally* consider a 70-200mm F4 to be as useful, on APS-C.

Direct link | Posted on Sep 22, 2014 at 17:47 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

sans culotte: "Equivalence theory" pushed by some guys is absurd cause it's never used to really compare systems. Why Richard Butler uses his "equivalence" only when talking about m43? Why he doesn't use it when talking about APS-C? Why he doesn't compare FF to medium format? If you wish you could call it DOF equivalence, but not equivalent aperture. Just cause aperture is focal length divided by diameter of entrance pupil. There's much easier to understand camera+lens capabilities dealing with some real physical numbers like Aperture, Focal length, ISO, not their pseudo-"equivalent" distorted versions.
Why is Pana 35-100 f/2.8 comparable to FF 70-200 f/5.6? To match the exposure I would need to push ISO 2 stops higher on FF which would result in higher noise despite all "light capture", is it somehow equivalent?

As an aside: we don't refer to it a depth-of-field equivalence because it isn't just about depth-of-field, as I tired to illustrate in [this article](http://bit.ly/equivap), using real-world examples, not just theory and calculation.
Look at it this way: the aperture in the Panasonic 35-100mm lens it 1/2.8th the focal length. (12.5-35.7mm diameter)

However, as soon as you think of the lens as behaving like a 70-200 on full frame (which [Panasonic does](http://www.panasonic.com/ca/consumer/cameras-camcorders/interchangeable-lenses/h-hs35100.html), on its website), then that same 12.5-35.7mm aperture diameter range would be 1/5.6th of 70-200. And the physics works as if it were, too (depth-of-field, diffraction, total light etc).

Direct link | Posted on Sep 22, 2014 at 17:32 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

sans culotte: "Equivalence theory" pushed by some guys is absurd cause it's never used to really compare systems. Why Richard Butler uses his "equivalence" only when talking about m43? Why he doesn't use it when talking about APS-C? Why he doesn't compare FF to medium format? If you wish you could call it DOF equivalence, but not equivalent aperture. Just cause aperture is focal length divided by diameter of entrance pupil. There's much easier to understand camera+lens capabilities dealing with some real physical numbers like Aperture, Focal length, ISO, not their pseudo-"equivalent" distorted versions.
Why is Pana 35-100 f/2.8 comparable to FF 70-200 f/5.6? To match the exposure I would need to push ISO 2 stops higher on FF which would result in higher noise despite all "light capture", is it somehow equivalent?

Actually the two stops higher ISO almost certainly wouldn't result in higher noise (assuming you're using contemporary sensors), but that's not really relevant here.

This article is almost solely about APS-C and comparing within that format - hence equivalence isn't relevant.

However, in the two places it is relevant: the box about Micro Four Thirds 70-200mm equivalents and the reference to using a 70-200mm F4 on full frame, it is referenced.

Direct link | Posted on Sep 22, 2014 at 17:28 UTC
In reply to:

rufusrm44: This statement is false:

"Quite simply, the smaller sensor will receive less light at matched exposures (same shutter speed and aperture) and this means more noise."

It's only true if the pixel pitch is lower (meaning the pixel density is greater.) But if the number and size of the pixels are identical, that less light received on the m43 sensor is equivalent to the 'more' light gathered by full frame because the full frame requires more light to cover the larger sensor.

Imagine if you had a sensor that was cut 1/4 the size of the full frame sensor. That means it only needs the same shutter speed and aperture to produce the same quality of image, but that image would be only 1/4 the pixels of the ff sensor, and would therefore only need 1/4 the light.

As was said further up, if you just use the APS-C crop from a full frame sensor (with the conditions you suggest), then yes, those two image should be identical.

However, if you use the whole of the full frame sensor then you'll have more light-collecting area (and hence lower noise when you consider the entire image).

Direct link | Posted on Sep 22, 2014 at 16:59 UTC
On Hands-on with Panasonic Lumix DMC-LX100 article (432 comments in total)
In reply to:

DerekWillmott: The specs sheet shows 2.7 megadots on the EVF. This article says 2.3.

Equivalent in a different sense.

This EVF produces resolution of 1280 x 720 pixels which, if you used one red, one green and one blue dot at each pixel, would be 2.7m dots.

This is a field sequential display: it displays red, then green, then blue information, in quick succession, so offers the same resolution as a 2.7m dot display would, but actually only has 1/3rd that many 'dots.'

Direct link | Posted on Sep 21, 2014 at 02:24 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

StevenE: The Sigma 50-150mm F2.8 weighs as much as a full frame 70-200 2.8, and that's a turn off. I might as well carry the FF.

I have owned a Tokina 50-135 f/2.8 (APS-C lens) for many years and it's a great lens, except it doesn't have IS. It's parfocal too, which is great for video!

I'm sorry, I mis-read the original comment (I read it as 'Samsung').

Yes, the Sigma 50-150mm is too big and heavy - it appears to be built in the same body as the current 70-200mm - which totally undermines the point of the lens, in my opinion.

Direct link | Posted on Sep 20, 2014 at 19:31 UTC
In reply to:

camerosity: You forgot the Nikon Coolpix A. Typical dpreview

[Really?](http://www.dpreview.com/articles/8545740747/opinion-why-the-death-of-the-point-and-shoot-benefits-photographers?slide=4)

Direct link | Posted on Sep 20, 2014 at 18:43 UTC
In reply to:

Jefftan: I have a question for someone in the know
Can lens filter be used on any of these 3 cameras? RX100 m3, G7X, LX100?
thanks

LX100 has a 43mm filter thread. Neither the Sony nor Canon has. Sony offers an accessory to add filters, this may also work with the Canon.

The RX100 III and G7 X both have built-in ND filters.

Direct link | Posted on Sep 20, 2014 at 18:38 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

Mark Chan: I wonder why you didnt't try to put the 35-100mm and 40-150mm f2.8s of the m43 system into this - yes I know you are discussing APS-C, but shouldn't such discourse include m43 too given that the photo quality is now there similar.

There is a section about the 35-100mm F2.8 towards the bottom of the article.

However, probably because it doesn't share a mount with a full frame system, you don't see mFT owners using or asking for 70-200mm lenses.

Direct link | Posted on Sep 20, 2014 at 17:54 UTC
On Opinion: Bring on the 70-200mm equivalents article (328 comments in total)
In reply to:

Knine: I like the fact that you now post equivalents of the focal length and aperture in you camera reviews. I wish that you would carry this over to other reviews like this lens review. Wouldn't the 50-150 be an equivalent of 75-225 on a 1.5 crop factor camera? And, the 70-200 would be 105-300? But more importantly, the F-2.8 would be more like F 3.8. I feel that by not showing these numbers you are perpetuating the sales myth that manufactures exploit. Please keep posting these numbers.

@phazelag - It is unfortunate that 135 film became the default reference point for describing angles-of-view in terms of the focal lengths that offer them. It's understandable, given that format's dominance in the film era, but it's unfortunate in that it appears to (falsely) imply the superiority of one particular format.

Ultimately all formats are a size/image quality (and usually price) balance. If you *only* care about image quality then the larger you can go, the better, and the Pentax 645Z's sensor is 60% bigger than full frame...

Direct link | Posted on Sep 20, 2014 at 17:27 UTC
On Hands-on with Panasonic Lumix DMC-LX100 article (432 comments in total)
In reply to:

DerekWillmott: The specs sheet shows 2.7 megadots on the EVF. This article says 2.3.

My mistake.

It's 2.7m dot *equivalent*.

Direct link | Posted on Sep 20, 2014 at 17:13 UTC
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