Saturday, May 26, 2012

Is it really better to not half-press to focus with the Fujifilm X-Pro 1?


Fujifilm's new camera uses contrast-detect autofocus, and the current Internet hand-wringing is over whether this is a horrible critical flaw or not. As often happens in such discussion, a bit of street wisdom has arisen: it's better to just push the shutter the whole way. For example, this blog comment:

AF speed on the XPro isn’t that slow, the problem is that most people use it as they would an SLR/DSLR for focusing, i.e half press the shutter and wait for AF confirmation then press the shutter all the way, in most cases with the XPro and the X100 you don’t need to do this.

And there's at least one thread on DPReview, but as characteristic for such discussions, there's a lot more smoke than fire.

The X-Pro 1 manual says nothing about this, and in fact says:

S (single AF): Focus locks while the shutter button is pressed halfway. Choose for stationary subjects.

In my experience, if the subject is stationary, the half-press method works as it always does, and if it's moving the full-press method isn't as good as using AF-C (continuous autofocus). I've used plenty of point-and-shoot cameras as well, which of course use contrast-based AF, and the half-press focus lock has always served me well.

But then, a lot of people are saying this is a big deal. Is there any reasonable basis, or is it just wishful thinking?

Asked by mattdm


No, it is not. There is nothing magical about not waiting at the halfway point.

What you read is silly, as if waiting would make the focus take longer or something. It does not work that way. You can press all the way as fast as you want and you'll get a shot in focus or not. The longer you wait at the half-press (in AF-S) mode or before fully pressing (in AF-C mode), the higher the probability the shot will be focused. Waiting too long might make you miss action but it won't make the camera miss focus.

Note, having an X-Pro1 one in hand and, for all I tried, I cannot see how not waiting at the half-press can improve focus.

Answered by Itai

What camera and accessories do I need for taking photos of paintings made with acrylics?


I currently have a 2 year old digital camera and am looking into taking professional photos of my artwork, mainly acrylic paintings. I was wondering, starting out, what is the best kind of camera and accessories that are required and which items might be a good idea to have. Would any digital camera work, or would a film camera be better?

I realize that if you take a picture with a film camera you can better guarantee the number of prints made; yet I want a digital copy of the final print (to do different things with) so that is not brought into account.

Asked by Kyra


Digital is better than film:

  1. easier
  2. film processing requires a pro lab.
  3. if using film, you should shoot on transparency which requires an accuracy of 1/3 of a stop.

Raw files have +/- 1 stop flexibility. Raw files have colour temp flexibility. Digital is more sensitive to subtle variations in tone ~ therefore You should mix daylight and flash lighting balanced across the exposure area. That's the best solution for paintings.

Answered by Ian Hobbs

How do I quantify the quality of a scan relative to the original?


For example, I imagine scan quality factors to assess include: color reproduction, scale, optical resolution, etc.

Only real comparison I have for what I'm attempting to understand is how a monitor color correction system allows you to at least know if there's a problem. Though it seems like the only way to know if a scanner was functioning correctly would be to have some sort of "industry" standard sheet to scan and then have read by some analytical software design to evaluate/quantify performance on predefined scanning reproduction factors.

Any suggests on how to quantify the quality of a scan relative to the original?

Asked by blunders


Take a look at web resources around colour calibration for scanners. Basically, you need to buy a colorimiter with an accompanying test target.

Answered by James Youngman

Is Flash a Must-Have For Macro Photography?


I want to start into macro photography this year so I've chose the Canon EF 100mm f/2.8L Macro IS USM lens to start with (I still haven't bought it since I'll do it next week, which I'll be in the US), but a friend that is really into urban photography suggested said to me that a flash is a must-have for macro photography.

The problem is that I don't like to use flash (examples), so I wanted to know if it's really a must or only a matter of choice.

Asked by Nathan Campos


I am not an expert macro photographer, but from my little experience I've understood that flash is NOT a must. However, in macro photography often we have to deal will DOF too shallow and even a mili-meter movement can change your focus drastically. For this, often you'll end up using f/11 or even higher to ensure that all parts of the subject you're shooting are in focus. Keeping f/11 and still getting a moderately fast shutter speed to avoid hand shake/movement blur isn't much of a problem in bright and sunny days but can cause you trouble if theres not much light or event its a little cloudy. So, its safer to carry a flash around, preferably a ring flash for macro shooting. Thus you don't take the chance and increase your keepers whether its broad daylight or cloudy.

Answered by ShutterBug

Looking for a reasonably priced wide angle lens [closed]


I have a Canon Rebel XS and recently I've been looking for a wide angle lens. Specifically, anything less than 28mm. Do you guys have any recommendations for me?

I'm looking for something in the $400 range if possible but feel free to suggest others too.

Asked by codedude


Have a look at the 'Tokina AF 12-24mm f/4 AT-X Pro DX'; a new model would cost you about $600, but you should find a used older model for the price you quote.

Answered by Gillie Bengough

Friday, May 25, 2012

How to measure distance to subject in Depth of Field calculator?


I used Depth of field calculator here.

I should specify subject distance.

How to measure distance to subject?

In theory this is a distance to front principal plane or point. What is in practice?

I tried to calculate expected image size and then made shot with camera. In calculation I measured the subject distance from front lens of photo lens. This result that "theory image" about 1.5 times larger then "practical image".

Asked by sergdev


According to the FAQ for the particular calculator you're using, the calculations are performed for a thin lens, and hence the front nodal point of the lens should be used. The author recommends using the front surface of the lens, on the assumption that the front nodal point is somewhere inside the lens, and this assumption will yield a conservative estimate of the DoF.

By the way, note that in lens specifications, focusing distances are specified from the film/sensor plane. This location is often marked with a special symbol on the camera body. So these measurements are not exactly comparable to what the DoF calculator uses.

Answered by coneslayer

Where do I find stock photography I can use on a Shopify theme?


I am working on a theme for Shopify, but they require that you provide some stock images inside your theme to demonstrate how your theme would work in a 'realistic' context.

The types of images that I'm looking for are product shots, and I need a set of images. For sake of continuity in design, they should all be taken within a similar context or style.

Is there such a resource?

Asked by Victor S


I would recommend using any stock site which provides galleries by the same photographer.

For example, ShutterStock and iStockPhoto allow you to browse other images by photographer. Just search for a single product shot, and then look at the photographer's portfolio for similar shots.

Alternatively, check the collections features which allow photographers and customers to collate similar images.

Answered by Maynard Case