digital imaging

full-frame vs crop-sensor comparison :  depth-of-field & perspective

When the differences between full-frame and crop-sensor cameras are discussed, there is an inevitable question about whether the crop sensor multiplies the focal length. Whether a 50mm lens on a crop-sensor acts like a 75mm lens (on a 1.5x crop sensor) or 80mm lens (on a 1.6x crop sensor).

The answers given on the photography forums are confusing – yes, the focal length effectively increases. No, it doesn’t. Two polar opposite answers. The discussion (which tend to devolve into arguments) are convincingly made for both sides. The reason is because the topic is a complex one … and therefore the answer is (kinda) complex too.

One argument goes along the lines that the crop sensor is just that, a crop. An enlargement. That nothing changes – you just get less of the scene. And that there is no “equivalent focal length” when you go to a crop sensor camera. But what really happens is more complex than that.

With this article, I want to help analyze what happens when you change lenses between a full-frame camera and a crop-sensor camera. And we’ll analyze whether there is actually an equivalency between certain focal lengths, when using a crop-sensor camera. In other words, whether your 50mm lens becomes “equivalent to” a 75mm or 80mm lens when used on a crop-sensor camera.

Since this article ended up being a long meandering discussion, I thought it best that we start with the final summary. Just to save the impatient people some work.

Summary:

Yes, a 50mm lens does indeed behave like an equivalent focal length of a 75mm lens (on a 1.5x crop sensor), or an 80mm lens (on a 1.6x crop sensor) … however, the depth-of-field increases by about a stop.

Yes, a 100mm lens on a crop-sensor camera will give you the same perspective as a 150mm / 160mm lens (on a full-frame camera), if you don’t change position … however, the DoF increases. (i.e., less shallow DoF)

But let’s discuss this with some images:

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finding interesting available light & white balance options

It’s always a feel-good moment to discover interesting available light while out on a photo shoot. Something unusual to add a new flavor to a different sequence of images.

While photographing a model with Tilo Gockel and Mike Silberreis (both from Germany on a visit to NYC), we started off with off-camera flash to help with the strong sunlight. (You might remember Tilo from a recent guest article on product photography on a budget.)

Then, while positioning Olena, I saw part of her dress had a patch of bright light on it. Turning around to see where this came from – I expected sun flare from nearby building window – I saw that it was actually the sun reflecting off a traffic sign right next to us. The light that was reflecting off this traffic sign was pretty hard, but had an interesting specularity, yet appeared flattering. So we shot an entire long sequence here, ditching the off-camera flash.

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post-processing workflow: solving a color banding problem in photos

Photographing people in the studio against a darker background, I’ve been plagued with banding problems. Some of it had to do with the limitation of working in an 8-bit environment in Photoshop. As described in this article – how to deal with color banding – a work-around was to editing images as TIFF, and thereby skipping a few steps where I would previously just have edited the JPG. The additional info in the TIFF file minimized color banding.

But then with darker backgrounds which have a bit of color in them, the problem still cropped up, as shown in the left-hand image. Then I stumbled on the cause of the problem – the camera profile in ACR / Lightroom.

At some point I had changed the camera profile away from the default – Adobe Standard – to Camera Standard. I liked the added contrast and saturation (as can be seen in the comparison above.) But this unknowingly, come at a cost – increased color banding in smooth transitions in darker tones. This isn’t something you’d notice in the background if it consisted of a landscape or an urban scene. But the moment you have smooth gradients of darker tones, this problem rears its ugly head.

It’s as simple a solution as that – keep the camera profile in ACR / Lightroom to Adobe Standard. Or, if you use a different flavor via one of the profiles you purchase, just be aware that this could be a problem.

I wanted to share this, since I spent an entire morning on Photoshop tutorials on dealing with color banding – none of which worked in this example. All it took was going back to the root – the camera profile used in editing the RAW files. If you see color banding in your photos, then perhaps, perhaps the solution is as simple as this.

Edited to add: The images were shot with the Nikon D810.

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post-processing workflow: how to deal with color banding / posterization

If you’ve ever noticed banding or  posterization in your photos, where you’d expect solid colors, then there’s a relatively easy fix for it. This posterization effect appears as bands of colors, where the transitions between similar tones aren’t smooth, but have jagged edges instead.

It is caused by the 8-bit JPG not having enough data to give you a smooth gradient when large blocks of color slowly change. You’ll often see it in the blue sky in landscapes, or as in this case, with large areas of color in the background. Actually, the image above doesn’t show this – I fixed it. Here’s how.

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improving a photograph by finessing it in post-processing  (models: Yulia & Anelisa)

While I’m a strong supporter of the idea to get it right in camera (as far as possible), there are times when massaging a photograph in Photoshop, can greatly improve it. And ultimately, it really is the final image that counts.

As a kind of companion piece to the photo of Anelisa jumping, here is a photo taken in the same area with the same kind of strong daylight. In using off-camera lighting here, the look of the photograph is inherently different. When I posted this image on Facebook as a teaser, someone guessed that it took “very expensive reflectors and an army of assistants”. Perhaps that was meant as a tongue-in-cheek comment, since my lighting is quite straight-forward. Or perhaps it does look like an image that could pop out of a Fashion magazine. I’m biased of course .

In deciphering how the photograph came about, let’s look at the straight-out-of-the-camera image …

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a favorite image – before & after (and the how to)

There’s something about this photograph that I really like … aside from Anelisa being one of my favorite models. It is slightly surreal with Anelisa’s apparent levitation. The dress and hat is reminiscent of a 1950’s Fashion, and Anelisa’s mid-air pose is also reminiscent of Philippe Halsman’s iconic jumping images. All that, combined with the sun flaring across her face and the washed-out background, all adds to this wonderfully nostalgic mood.

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wedding photography: 3 tips to speed up your editing workflow

One of the questions that came up during the Q&A at yesterday’s presentation at B&H, was how long does it take me to edit a wedding. Well, the ideal is that it takes me less than a day. During the peak wedding season around September and October, it is easy to slip behind, but that still remains my goal – to edit a wedding during the week right after the wedding took place.

There are several things motivating this idea:

  • I am more likely to get print orders from the guests at a wedding if the event is still fresh in their memory.
  • In terms of your workflow as a photographer, it is imperative that you don’t fall behind. If you don’t edit a wedding *this* week, then you’re behind because you’re shooting further events.

The best idea then is to edit the wedding in the day or two directly after. Cull, edit, upload, and then you’re done with the immediate workflow. Keep things rolling.

Here are my 3 best tips for a faster workflow. Of course, this doesn’t just relate to weddings, but also to any event where a high volume of images need to be dealt with.

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Ulorin Vex bounce flash portrait

bounce flash portrait & Photoshop retouching technique

When we were done with the studio shoot with Ulorin Vex, we still had a few minutes left, so I thought I could do a bounce flash portrait as well. Just for a comparison of sorts to show that on-camera bounce flash can give interesting results too. Here is the low-key portraits we did with the Profoto set-up.

The only semi-interesting background I could find in the studio (that wasn’t a white wall), was this grungy green door to one of the store-rooms. I thought it might work as a gritty urban setting. I shot about eight frames in the tight corner, but didn’t like what I saw on the back of my camera, so called it a day. We were done.

Looking through the images again today, cleaning up my hard drives, I hovered over the first image I took and thought it might hold some promise still if I worked it a little bit in Photoshop. Here is where I started …

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off-camera flash for a photo session with a Vintage look

Anyone who regularly follows the Tangents blog or has my 2nd book, off-camera flash photography, might recognize Sarah. When she told me she was visiting New York, I made sure that I squeezed in a photo session with her in my schedule. The weather on the day was grey and drizzly … enough reason to juice it up with some off-camera flash. And then play with the images in post-processing a bit …

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Photoshop plug-in for a film look – Nik Color Efex Pro 4

For a part of the individual workshop we did yesterday, Anelisa wore this cute outfit with a bit of a retro look to it. I loved her spontaneous pose here as well. In editing the image, I thought that an “old school” film look to it might suit the final photograph very well.

In previous examples shown here with a vintage look to the photograph, I had used the Totally Rad action sets. This time I wanted a specific film look to it, so I went with Nik Color Efex Pro 4 (B&H). This Photoshop plug-in has a 55 different filters. And of course, I like things which are easy to use.

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