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A Standard Time Reminder

November 8, 2011 2 comments

Categories: Photo Tips

Two Hosers Photo Show- Full Frame vs Crop Sensor Revisited

September 22, 2011 Leave a comment

The following series of posts were recently referenced on Episode 56 of The Two Hosers Photo Show.

I recently dusted off my Sigma 30mm f1.4 lens that I had been using with my Canon 40D. Once I upgraded to the 5D I figured that setup became redundant because I could achieve the same (except better) result with the full frame camera and the 50mm f1.4. I was right.

Then my “40D Walking Around 17-85mm” broke so I unretired the 30. I found myself in situations where I wanted to bring a DSLR but really didn’t feel like carting along the tool that buys my kid new shoes. Not that I would be thrilled if somebody spilled punch on my 40D but it wouldn’t be nearly as drastic.

So with that epic backstory behind us I decided to shoot a quick test comparing the 30mm on a crop vs the 50mm on a full. Buckle your seatbelts, here we go.

I tried to shoot both photos from the same angle and distance as best I could. Both cameras have identical settings but you can see slightly different exposure/colour results.

The first set was shot at f2.8 with the focus being set on one of the leaves of the tree on the beige t-shirt. Aide from the slight framing differences (I based framing on the focal points in the viewfinder. Turns out they are not identically placed in each camera…..) the images dont look wildly different to me. I would suggest there are subtle differences in the DOF as evidenced by the lettering on the beige t-shirt but if these weren’t viewed side by side I think you would be hard pressed to distinguish.

Where we do notice the difference is in the shape of the suitcase. Because we are using a wider angle lens to achieve the same framing as a standard 50mm lens, our perspective changes slightly. This results in the slight distortion of the suitcase. Once again I feel that if these photos were viewed independently nobody would complain about the warped suitcase, but when shooting a close up portrait of someone we might not be doing them any favours.

Next, I moved in slightly and cranked both lenses wide open to f1.4. In this case the focus is on the “A” in nature. This comparison illustrates the subtle difference in the shallow DOF.

I much prefer the image from the 5D but only when compared side by side.

Conclusion? This test confirms my earlier assessment that full frame is awesome and I recommend getting one if you can get it to pay your bills. If not, go with the crop sensor. You’ll save a few Deutschemarks and the chicks will still dig you.

Two Hosers Photo Show- Full Frame vs Crop Sensor pt4

July 21, 2011 1 comment

The following series of posts were recently referenced on Episode 56 of The Two Hosers Photo Show.

One last note about crop sensors for now (I have not talked very much about EF-S lenses and I am not going to).

One of the catch phrases you hear with the crop sensors cameras is the “Equivalent Focal Length” or some variation. With the Canon sensors you get a crop factor of 1.6 (Nikon is 1.5) so you’ll hear a lot of folks saying things like “The 50mm lens on the 40D is the equivalent of an 80mm lens”. While there is some truth to this statement it is essentially a shortcut to explain what is actually going on.

True, the “Field Of View” is roughly equivalent to an 80mm lens in terms of how wide the camera can see but that’s about where the comparisons end. Because it is still a 50mm focal length cropped you get the characteristics of a 50mm lens.

I shot a couple of test pics to try and illustrate this point. The first photo was taken with a 50mm lens set to f4 on a Canon 40D (crop sensor). Next I made the exact same shot, from the same distance with a Canon 5D mkII (full frame) and a 70-200mm set to 80mm at f4. (Okay, I missed slightly and it was actually 78mm if you want to split hairs). Do these images look identical?

The two photos are fairly similar but on close inspection you can see the subtle differences you get when using a proper 80mm lens. In order to further illustrate this let’s try an experiment.

I shot two images of the same subject with my Canon 40D using my 17-85mm lens. I made the first shot zoomed all the way in at 85mm.

I then attempted to recreate the same shot zooming all the way out to 17mm. I didn’t change any other parameters (specifically distance from camera to subject). I then cropped in post to give me a similar framing, just as a crop sensor would do.

You can see a big difference in these two images in terms of Depth Of Field. Shooting a 17mm lens on a smaller sensor (crop factor of 5x in this case) is clearly not the “equivalent” of shooting with an 85mm lens.

Keep in mind that the results here are exaggerated by the 5x crop factor vs the 1.6x that we normally get. So while it is “similar” it is not “equivalent”. As I mentioned in the previous post however, I wouldn’t toss my 7D in the bin just yet.

Two Hosers Photo Show- Full Frame vs Crop Sensor pt3

July 20, 2011 1 comment

The following series of posts were recently referenced on Episode 56 of The Two Hosers Photo Show.

In parts one and two we talked a little bit about the difference between crop sensor cameras and their full frame cousins. Specifically we were asked about the effect on Depth Of Field. The basic conclusion was that sensor size does not affect DOF- when all things are equal.

That means that the same lens, same aperture and same distance from camera to subject yields the same DOF results. But obviously the pictures themselves are quite different. The initial assumption is that the crop frame sensor “zooms” in on the image but that is only partly true. In reality since it only uses the center part of the image it is in fact “cropping” the image but when printed the same size (in this case 800 pixels wide) it effectively zooms the image. Because the “zoom” is done in post it doesn’t have the same effect optically as a true in camera “zoom” would. Let’s have a look. (To recap- all images were shot with a 50mm lens at f4).

Here’s the full frame image again.

Now here is the image from the crop sensor as it would appear in relation.

Looking at the image you can see where the rest of the picture would be captured if we used a full frame. (NOTE- I actually tried to centre the image better than that but I missed. Sorry.) But to illustrate the point even further, let’s look at the two images laid on top of each other. The black and white is the extra picture captured the 5D’s full frame sensor.

So that’s where sensor size doesn’t affect DOF. Now let’s see where it DOES change the result. In order to achieve the same framing as one would get with the full frame 5d, the crop sensor user has to back up. Since one of the main factors of DOF is distance from subject to camera, and we are now changing that distance we can expect the DOF to increase (less blur).

Not only is our DOF affected, our perspective also changes slightly. Another way to achieve similar framing would be to use a wider lens on the crop sensor. For instance the 30mm 1.4 from Sigma is popular as a 50mm equivalent. However, since another main factor of DOF is focal length, using a shorter focal length with also result in a deeper DOF and a different perspective.

In the end the results in DOF don’t appear to be overwhelmingly different so my advice is to be happy with your crop sensor camera and go out there and make some great photos. Remember, it is likely 10 times the camera you were shooting with just a few years ago.

PS- I did shoot one more test, the results of which I will share in the final post in this series. Stay tuned.

Two Hosers Photo Show- Full Frame vs Crop Sensor pt2

July 17, 2011 2 comments

The following series of posts were recently referenced on Episode 56 of The Two Hosers Photo Show.

In part one of this series we talked a little about the physical differences between a full frame sensor and a “cropped” sensor. Now let’s see what happens where the rubber meets the road.

This is where it gets a little complicated and the arguments start. For the sake of simplicity we will only deal with “full frame lenses” and not “cropped sensor lenses”. After reading the first post some of you may have wondered aloud, “If the sensor only uses a small part of the circle, then why not make a smaller lens with a smaller circle?” Well, they do. Canon, for example, makes a few lenses called EF-S that are designed specifically for the Crop Sensor cameras and are meant to be cheaper. The downside is that they do not fit on a full frame camera. In the interest of trying to compare apples with apples (if you are offended by that reference you are just looking for trouble) we will only compare full frame EF lenses.

The original listener question asked if there was a difference in the DOF when shooting with a 50mm 1.8 on a Crop Sensor camera vs a Full Frame. The answer is “NO, there is no difference.” Wait a minute. Sort of. So, “YES, there is a difference”.

Since I own a 40D (crop), a 5D mkII (full frame) and a 50mm f1.4 lens I decided to put it to the test.

Let’s deal with the “NO DIFFERENCE IN DOF” answer first. In order to demonstrate the difference I set up the shot with as many constants as possible- the cameras mounted on a tripod so the distance to subject is the same, aperture set to F4, shutter to 160, WB to Daylight, and the same 50mm lens for both shots. The only difference is the two cameras. Let’s compare the result-

Ignoring the obvious, let’s focus our attention solely on the DOF. To my eye it looks close enough to be called identical. And so it should, nothing has changed optically. Since the DOF is a function of the aperture, focal length, and distance from the camera and those values are identical in each shot we achieve the same DOF.

Remember though, that I did say it DOES affect our DOF. That part is still true but to illustrate we need to explore what is causing the obvious differences in these two shots. We’ll do that in part 3.

Stay tuned.

Two Hosers Photo Show- A Little More About Flash

July 16, 2011 Leave a comment

Adam and I have been talking quite a bit about flash photography on the show lately. The technology is such that shooting basic flash photos on AUTO settings is fairly straightforward and yields pretty reasonable results. But moving into more manual settings, while ultimately rewarding, can be daunting at first. However, if you can grasp one simple concept you will be well on your way to making great looking flash photos.

When shooting with flash you are essentially making 2 exposures. One for the ambient light, and one for the flash.

Allow me to illustrate with a couple of examples. Here you can see a photo I call “Flowers In The Hallway”. It is undoubtedly a terrible picture but it helps me illustrate my point and there’s no sense distracting you with a Rembrandt.

In this first set we establish the ambient light setting (i.e. the existing window light) and then adjust our bounce flash accordingly. First we start with no flash.

Next we add very little flash.

That barely makes a dent so we add more.

Starting to see some results so we add still more.

And a little more.

And finally we max out.

Full power is clearly too much so we would scale it back a little to get the effect we wanted. Notice in each picture that even though the flash was getting brighter we left the ambient light (the window) consistent? Now let’s try the opposite effect. We’ll leave the flash output consistent and adjust the window light.

In the first shot we overexpose the window to blow it out a little.

Next we reduce the exposure to include less ambient light.

And even darker.

And still darker.

Like our first example, notice how the flash exposure remains consistent while we alter the ambient exposure.

Tune in next week to hear Adam and I explain how to build a flash photograph and balance the two exposures. www.twohosers.com

Two Hosers Photo Show- Full Frame vs Crop Sensor pt1

July 15, 2011 2 comments

or “Much Ballyhoo About A Molehill In A Teacup”.

The following series of posts were recently referenced on Episode 56 of The Two Hosers Photo Show.

I’ve been meaning to write about this one for a long time but never really got around to it until I got an e-mail from a listener asking about it. So let’s wade into the murky waters of Sensor Croppery.

This topic inspires a whole lot more confusion and argument than it really should. It’s both simple and kind of confusing simultaneously. Maybe because there are a lot of different misinterpretations floating around the web and people have dug their heels in on what they think is going on. On that note, I’ll do the same.

Keep in mind I am not a Camera Designer, nor a Sensor Engineer. Aside from the time me and a buddy created Kelly LeBrock I am not really a scientist. Weird. So what follows is MY UNDERSTANDING of what crop sensor is vs full frame.

Why The Difference?

(NOTE- Aside from mentioning it right now, we will not talk about megapixels in any of these posts. It is irrelevant to this discussion.)

Traditional 35mm film got it’s name from the fact that it is 35mm wide. Almost. In truth it is 36mm wide by 24 mm high. When the transition to digital was made that physical sensor size was mimicked. Really awesome, very expensive. But smaller sensors are cheaper so they started making those in order to make DSLRs available to more people. Different camera makers opted for different sizes (slight variables) but since I shoot Canon I’ll refer to those.

The so called “crop sensor” cameras feature a physical sensor 22.2mm by 14.8mm. These also became known as 1.6 sensors since 36/22.2 is approx 1.6. (And by extension the “true” focal length of lenses on a crop camera could be calculated by multiplying by 1.6. Thus, a 50mm lens is the equivalent of an 80mm on a full frame camera. Or is it? More on that in a later post.)

Before we dive too far into all the math involved let’s have a quick look at what is physically happening here through the use of a couple of diagrams. In the first one we see an approximation of the image your lens registers. Since your lens is circular, so is the resulting image.

The only thing is, we don’t capture the whole thing since we deal with rectangles. So when we employ a full frame (36mm x 24mm) sensor we capture this portion of the image.

And when we employ a cropped sensor (22.2mm x 14.8mm on the Canon) we capture this much of the image.

As you can see the smaller sensor captures what appears to be a crop of the larger image, hence the term “Crop Sensor” or “Crop Factor”.

So, does it matter? Well that depends. Some people say it matters very much and others insist it is entirely irrelevant. Good news is that both camps are right. I’ll explore how this all affects our image making (especially DEPTH OF FIELD) in the next few posts.

Stay tuned.

The Two Hosers Photo Show Video- What Is High Speed Sync?

June 25, 2011 Leave a comment

*NOTE*- The lip sync seems to drift towards the end of the video. I have no idea why. I suppose there is a certain type of irony when the sync drifts in a video about sync.

Two Hosers Photo Show- Unlikely Accessory

June 15, 2011 Leave a comment

One of the most invaluable accessories you can keep in your camera bag is a small step ladder. Ok, technically not in your bag, but you get the idea.

It comes in particularly handy when you are taking someone’s headshot and you want to maximize their positive features while minimizing the not so positive ones. Depending on your subject mileage will vary but it is safe to say that everybody looks better from a slightly downward angle vs straight on. (This is generally a pleasant euphemism for “double chin de-emphasization”)

As an example I shot a quick series of 3 headshots of Meike. Now, as it turns out Meike has very strong, photogenic features (just the one chin) so the differences are very subtle but they are noticeable. The first shot is straight on, second shot is from one step up and the last shot is from the second step.

Even though the difference is subtle in this case I always make sure I have the step ladder on hand for this kind of shot. (Shot with Canon 5d MKII and 70-200mm f4L).

Be sure to check out The Two Hosers Photo Show for more tips on getting the most out of your DSLR. Subscribe free on iTunes or at www.twohosers.com.

The Two Hosers Photo Show- What is ETTL?

June 9, 2011 Leave a comment

 

We’ve talked a lot on the show lately about using your flash and something called “ETTL”. This video will give you a quick explanation about what is going on behind the scenes. More accurately, what is going on in front of your eyes. Just really, really fast.

For more subscribe free in  iTunes or go to www.twohosers.com