Long Lens & DOF

Today I wanted to share with you an image I created during our Gibbs Garden Workshops a few weeks ago.  

I had to take 2 images to create this image and then do a little Photoshop work, but it was so simple it's crazy.  The reason I had to do this is because I had an object in the foreground I wanted in focus and an object in the background I wanted in focus.  I was shooting with my Tamron 150-600mm Lens @ 600mm.  Shooting lenses that long, your Depth of Field decreases drastically.  I shot these images at an aperture of F/11, which you would normally think would be great enough to cover your entire scene.  It would, if I was using a wider lens, but like I mentioned the depth of field is so shallow with these longer lenses, even at F/11, I had more shallow a depth of field than I wanted.  Let me show you what I mean.

ISO 100, 600mm, F/11 @ 1/50th second

In the above image you can see I focused on the frog in the background and it is in sharp focus, but the foreground frog is pretty soft.  That's due to our limited DOF with the long lens.

ISO 100, 600mm, F/11 @ 1/50th second

Now in this image you can see the exact opposite.  I had focused on the foreground frog and it is in sharp focus, but we've lost the background frog.

How do I remedy this?  I take those two images you see above, I highlight them both in Lightroom, right click and choose "Edit In" and then choose "open as layers in Photoshop".  Then after they are loaded into Photoshop.  I highlight both layers, then go to the Edit menu and choose "Auto-Align Layers".  Once that is done, I choose one of the images, it really doesn't matter which one, then I create a "layer mask".  Then I can take my brush tool and using the opposite color of my layer mask (if my layer mask is white, I would use a black brush and vice versa) I can simply brush the out of focus frog into focus.  The resulting image is below.

You can see that both frogs are in sharp focus here in the final image.

You might ask why I wouldn't just crank up my aperture and take one shot.  Well, in this case, I was shooting at F/11 and had a shutter speed of 1/50th second.  I didn't want to slow my shutter speed any more.  If I had and one of the frogs moved, I would have had a blurry photo of a frog, with nothing I could do about it.  

Another thing to mention is that you need to shoot both images on a sturdy tripod so your camera doesn't move.   I would also advise you use a tripod @ 600mm and 1/50th second ;) I've started using Sirui Tripods and camera support equipment.  I couldn't be more happy with these tripods.