Richard Butler

Richard Butler

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

Comments

Total: 2309, showing: 41 – 60
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On Panasonic Lumix DMC-FZ1000 First Impressions Review preview (1282 comments in total)
In reply to:

Autoxave: The specs of of this lens is 25-400 mm/2,8-4. In terms of a FF sensor this will translate (equivalence) into 9-148 mm/5.6-10,8?

Autoxave: it depends on how cynical you're feeling:

If you're convinced they're out to get you, you could say that manufacturers are trying to **hide the truth** from people and avoid drawing attention to how terrible and limiting the compact cameras that they've been selling us are.

Alternatively, it was a genuine attempt to communicate the zoom range that a lens offers. While also, given the use of a sensitivity standard that tried to mimic the system used in film (which cancels-out the effect of sensor size), tell you the number that's relevant for exposure.

[Equivalent apertures](http://www.dpreview.com/articles/2666934640/) tell you interesting things about comparative performance and capability between systems, but they're not necessarily hugely *useful* while shooting, unless you completely dismantle the ISO system.

Direct link | Posted on Jul 9, 2014 at 00:10 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

DoctorJerry: Aperture equivalence
I ran a test using my Panasonic LF1 and selected sensor sizes of 12MP, 8MP, 5MP 3MP and 0.3MP. I can select those sensor sizes by using Panasonic’s EZ Zoom which trims off pixels on the perimeter of the sensor to arrive at a smaller sensor. As I read your article, I should have been needing either a higher ISO, slower shutter speed, or faster aperture as I trimmed pixels from the sensor. I found NO difference my test shots, all shot at 1/80sec, F2.0 and ISO 200, they were the same REGARDLESS of the size of the sensor I used.

Where I think you went wrong is in talking about how much less light reaches the sensor as the sensor gets smaller. What you overlooked was that the same quantity of light reached the plane of the sensor but since the sensor was smaller, it captured less light. It did NOT need all the light reaching the plane of the sensor, only enough to cover the sensor itself. According to my test f2.0 is 2.0 regardless of the sensor size.

The article tries to make clear that the nature of f-numbers (which guarantees light intensity) and ISO (which guarantees image brightness), come together to give the results you observe.

As such, the article doesn't say that you *need* to change ISO or shutter speed.

However, blow all your images up to the same size and you'll find the smallest crop is noisier - it's received the same light per-unit-area, but this means it's received less light in total (since the area captured is smaller). Far from ignoring this point, much of the article *makes* that point.

The least-cropped image received the most light in total. If you're saying that it didn't *need* this extra light, compared to the smallest crop, then you're effectively saying you could have reduced the ISO (and shutter speed) and still got the same total light as the smallest crop. At which point, you've understood it.

Direct link | Posted on Jul 8, 2014 at 23:59 UTC
On Panasonic Lumix DMC-FZ1000 First Impressions Review preview (1282 comments in total)
In reply to:

Markol: I've been a huge fan of Jeff for many years but the final thoughts he put together destroy much of his reputation IMHO.
While I'm not at all against this camera, an enthusiast would never argue that he doesn't print large anyway so the inferior IQ is ok when going on a once in a lifetime holiday.
But amazon will be happy with the text, that's for sure.

Overlooking that fact that most cameras are really good, we actually don't always give awards. We also have to face hugely aggressive criticism from our readers every time we don't give a camera our highest award. By comparison, no manufacturer or advertiser has ever expressed an opinion, to the best of my knowledge.

I'm not willing to be attacked every time I don't give a Gold **and** told that we are a soft-touch. There are many, many worse offenders on that score.

Jeff quite honestly set out the trade-off he's willing to make and what cost he pays for doing so (something I can't imagine an advertiser would encourage). In doing so, he was much less promotional than your description of it as being 'super nice.'

Unless you're suggesting that we can only give awards to full frame DSLRs (which are not exactly the optimal tool for most people), then it's legitimate to like a camera despite acknowledging the trade-offs.

Direct link | Posted on Jul 8, 2014 at 23:46 UTC
On Panasonic Lumix DMC-FZ1000 First Impressions Review preview (1282 comments in total)
In reply to:

Autoxave: The specs of of this lens is 25-400 mm/2,8-4. In terms of a FF sensor this will translate (equivalence) into 9-148 mm/5.6-10,8?

@Denis de Gannes - the lens is **not** 25-400mm.

It is a 9.1-146mm F2.8-4.
Such a lens is *equivalent* to a 25-400mm F7.6-10.9 on a full frame camera in terms of depth-of-field, angle-of-view and total light per image.

What I wrote acknowledged the true F number (used for exposure) and stated the most directly comparable lens on full frame. I didn't say this *is* an f/7.6-10.9, I said it was *equivalent* to one. Which is absolutely true.

Direct link | Posted on Jul 8, 2014 at 23:39 UTC
On Panasonic Lumix DMC-FZ1000 First Impressions Review preview (1282 comments in total)
In reply to:

Markol: I've been a huge fan of Jeff for many years but the final thoughts he put together destroy much of his reputation IMHO.
While I'm not at all against this camera, an enthusiast would never argue that he doesn't print large anyway so the inferior IQ is ok when going on a once in a lifetime holiday.
But amazon will be happy with the text, that's for sure.

There are very few cameras that take better photos than the 5D Mark III, in the grand scheme of things, so it's not surprising that there's an IQ cost to be paid for the FZ1000's much greater portability and much lower price tag.

Jeff hasn't said the IQ is bad (it's actually very good, especially for a compact), just that there's a trade-off to be made. And I don't think he'd be the only person willing to sacrifice a little bit of absolute image quality in order to take a camera that he could actually face carrying around.

I've known people to want a holiday in addition to the photographic opportunities.

Direct link | Posted on Jul 8, 2014 at 23:28 UTC
On Panasonic Lumix DMC-FZ1000 First Impressions Review preview (1282 comments in total)
In reply to:

Autoxave: The specs of of this lens is 25-400 mm/2,8-4. In terms of a FF sensor this will translate (equivalence) into 9-148 mm/5.6-10,8?

The specs are:
9.1-146mm, F2.8-4,
which is equivalent to:
25-400mm, F7.6-10.9 in full frame terms.

The progression through the lens range [looks like this](http://www.dpreview.com/previews/panasonic-lumix-dmc-fz1000/images/apertures.png).

Direct link | Posted on Jul 8, 2014 at 23:19 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

HeyItsJoel: That's it. I'm going full frame.

I was sold between micro 4/3 and APS-C cameras because of their small footprint. But after reading this, I've decided that anything worth doing in photography is worth doing right.

The thought of having to lug all that heavy equipment around while traveling definitely sucks. But in the end, image quality should not be sacrificed. This couldn't be more important when traveling to a location I will be more likely to go to only once in my life. That means getting it right the FIRST time.

Why not go to medium format, then?

Direct link | Posted on Jul 8, 2014 at 22:03 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

Lee Jay: "Any two lenses 25mm diameter apertures will give the same depth-of-field of shot at the same shooting distance."

This sentence is still incorrect, Richard.

The examples I've shown suggest otherwise - a 100mm F4 on full frame and a 50mm F2 on a Four Thirds sensor. In this instance there's a small complication added by the difference in aspect ratio but they offer the same angle of view and near-identical fields of view at any given distance. (A 67mm F2.7 for APS-C solves the aspect ratio problem).

Direct link | Posted on Jul 8, 2014 at 07:48 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

Average User: Richard:
I think this is useful from this point of view: When deciding what camera to purchase, it's important to realize that the larger sensor receives more light at the same actual f stop. So an aps-c camera with an F 1.8 lens is not getting the same total light as a full frame camera with the same F rating.

One issue has been bothering me, however. I can see where using a lens designed for full frame, and used with a crop sensor would be delivering less light to the crop sensor. But a lens designed for an aps--c camera would be bending the light to deliver it all to the aps-c sensor, so that if the lens diameter was the same, light to the aps-c sensor would actually be more intense, but total light could be close to equivalent.
Why is this wrong?

Let's assume the lens is a 50mm F1.8 full frame lens.

If you made an APS-C specific 50mm F1.8, you'd still get a 75mm equivalent field-of-view (the inner red cone in the diagram). The only difference would be it couldn't ever project a wider field-of-view if fitted on full frame.

Direct link | Posted on Jul 8, 2014 at 07:16 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

sertsa: Saw the headline and thought "Wow! an article about Alfred Stieglitz!" Oh well.

Sorry about that: it wasn't me who chose the term.

Direct link | Posted on Jul 8, 2014 at 06:58 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

TN Args: Even when you have converted for similar angle of view and depth of field, you don't have the same perspective and don't have the same shutter speed.

So there is no such thing as equivalence. There are only a number of conversion factors, each to answer a specific question.

Truth is, this entire topic is nothing more than an excuse for endless snobby trolling by full frame camera users. Sad to see, really.

If you're using equivalent focal lengths, eg 90mm equivalent lenses on *any* system, then it's reasonable to assume you would shoot at the same distance from your subject (to get the same framing). It's this working distance that defines the perspective.

This is why there's no perspective change between the 32mm lens (on one inch), and 85mm lens (on full frame), in this article.

There's also nothing to say you can't have the same shutter speed at equivalent apertures (as per the low light example).

Direct link | Posted on Jul 8, 2014 at 06:52 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

Lee Jay: "Any two lenses 25mm diameter apertures will give the same depth-of-field of shot at the same shooting distance."

This sentence is still incorrect, Richard.

I've corrected it to: 'Two lenses offering the same angle-of-view with 25mm diameter apertures will give the same depth-of-field of shot at the same shooting distance.'

Direct link | Posted on Jul 8, 2014 at 02:15 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

Jimmy jang Boo: When I choose a camera, equivalence is the last thing on my mind. Many folks have never handled or shot with a FF, so that point of reference is hardly axiom.

It is simply *a* point of reference (a common reference point in the sense that they refer to the same thing, not that FF is especially common any more). I'm not for a moment suggesting thinking 'what proportion of a FF camera's capability am I getting?'

But, if you're trying to decide between a 1/1.7"-type camera or a 1"-type one, then this would help understand the aperture ranges each offers, on a common basis. The same goes for deciding between an APS-C model and a Micro Four Thirds one.

Direct link | Posted on Jul 8, 2014 at 00:48 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

bmoag: An F stop is a ratio: it is as immutable as pi.
Pi does not change regardless of the size of the circle. There is no equivalence for pi derived from circles of different sizes, pi is always equal because pi is a ratio.
A smaller sensor captures less total light from the same lens than a larger sensor: if this is a revelation to you there is a bridge for sale in Brooklyn in which you may be interested.

@bmoag - The article doesn't say that the f-number changes.

"[The F-number itself doesn't change with sensor size, just as actual focal length doesn't change with sensor size.](http://www.dpreview.com/articles/2666934640/what-is-equivalence-and-why-should-i-care/2#equals)".

Direct link | Posted on Jul 7, 2014 at 23:26 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

PicOne: What.. no discussion of speed boosters?

And risk confusing things even further?

In theory I could have drawn an extra part of the rollover at the top of page two, adding an extra element that condenses the outer cone of light down into the APS-C region, giving the same light gathering ability and effectively decreasing the f-number.

Doing so would have further complicated the article and really pushed my Illustrator skills.

Direct link | Posted on Jul 7, 2014 at 21:26 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

HB 101: Run for your life Mr. Butler!

The geeks and nerds of DPReview are forming a mob as we speak and coming after you!

(Only one of those statements is true)

Direct link | Posted on Jul 7, 2014 at 20:51 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

HB 101: Run for your life Mr. Butler!

The geeks and nerds of DPReview are forming a mob as we speak and coming after you!

I'm actually on vacation today.

I'm currently writing from a secure bunker in an undisclosed location.

Direct link | Posted on Jul 7, 2014 at 20:51 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

Fabio Amodeo: Interesting article, but… If I think to real life situations, the equivalence matter seems to me much less important. Let me explain.
Situation A. I'm at a concert, with very little light. I'll take out the fastest lens I have, and bump up ISO. In theory FF is better, because it should give me better high ISO. But the faster lens I use wide open might have too thin a focus. My problem is not how much out of focus is the background; my problem is to have something in focus at all. So I'll stop down, and lose the ISO advantage.
Situation B. I have to shoot food, and I want all the food creverly prepared by the occasional masterchef to be in focus. Here a smaller format should have an advantage, due to bigger dof given the same perspective. But I know I'll be in full diffraction-danger zone by f/11, where many FF lenses are still good. And I know tilt lenses were made for this, but I'm too lazy or too poor to own one, Conclusion? It's always a compromise we live in.

Situation A: You say stopping down loses you the ISO advantage - what's that if not considering the effects of equivalence?

Situation B: The smaller system does not have a depth-of-filed advantage. If you stop down enough to get the desired depth-of-field, you'll get the same diffraction on both systems.

Yes, it's always a compromise - the idea of this article is to help people understand which areas the trade-offs are being made in.

Direct link | Posted on Jul 7, 2014 at 20:50 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

olypan: What is the fundamental motivation behind this article. Could it be to stem the tide of discontent with the Canikon duopoly and the realisation their end is near?

@olypan - the motivation is the constant arguing and confusion around this topic - and the resurgence in the light of Tony Northrup's video. The timing is prompted by me being able to get hold of all four of the 85mm equiv F1.2 lenses I used.

As I point our in the article - we are not saying 'full frame' is an optimal or even preferable format. It's just used as a reference point because it's well understood.

However, in terms of light capture, a bigger sensor is (except in extreme circumstances) better. Medium format is better than full frame, in this respect.

However, size, price, weight, lens availability and all sorts of other factors are also relevant when choosing a camera.0 Equivalence makes it easier to understand the trade-offs being made by *all* systems. It doesn't favour any one balance between those factors.

Direct link | Posted on Jul 7, 2014 at 20:20 UTC
On What is equivalence and why should I care? article (1830 comments in total)
In reply to:

JanMatthys: DPreview completely missed the point and fell for the marketing crap.

If you want to know the "equivalent" all you have to do is take a FF image and CROP IT by either x1.5 x2 or x2.7.

A 36mp sensor like the Nikon D800 will provide a decent 6mp image at the highest crop factor of x2.7 which is fine for a prints up to 8 x 10

If you need higher resolution at x2.7 and you find yourself cropping your images up to x2.7 very often then you should buy a 1" sensor camera, otherwise a FF sensor and good glass is really your most versatile option

Would you like to explain how this is marketing-related? If so, whose marketing?

Direct link | Posted on Jul 7, 2014 at 20:14 UTC
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