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No Auto-ISO(? or !)

May 4th, 2011

“The last thing you want to do is to let the camera decide what ISO setting to use”

Heard/read this already? I am pretty sure. With one exception (see the end of this post) I (naturally disagree.

First thing: It is not true that Auto-ISO (in a Nikon) silently jacks up your ISO. When Auto-ISO wants the camera to leave the base ISO you dialed in the Auto ISO mark will blink in the viewfinder. It is something that moves in the viewfinder - hard to ignore, much harder at least than forgetting the settings from last night’s binging:

So I just got my *** lens this week and I was super excited to break it in today at an outing to the California Academy of Science, which was a lot of fun and presented a handful of photography opportunities. Unfortunately I made a grave error…. I forgot to check my settings and my ISO was set to 1250 the entire day!! it was definitely unnecessary to have that setting so high and it ruined my pictures quality!

Outch.

What is wrong with Auto-ISO: It is in its current implementation too static (Ken Rockwell figured this out years ago *)

  • the AS-mode is of very limited use, you have to switch Auto ISO to shoot manual (luckily it gets ignored when using a flash)
  • It ignores the focal length - idiotic to enforce 1/250s shutter speed at 18mm
  • It ignores VR

What controls do we need

  1. Max exp. time (default 1/60)
  2. Max exp. adjust: absolute, relative (default relative)
  3. VR exp. adjust (default 3)
  4. Disable in manual (default on)
  5. Max ISO (default 1600)
  6. Allow underexposure (default off)

Max exp. adjust absolute is what we have now, relative means that the Max exp. time will be computed relative to a 50mm lense. So the 24mm lens will use a Max exp. time of 1/30 and a 200mm lens will not go below 1/250

VR adjust - dial in 1 (options should be 1,2,3,4,6,8,12,16,24,32) to not prolong the Max exp.time when VR is activated, otherwise the factor is appled- in the default example a 50mmVR lens would let you go down to 1/20. Perhaps a stops scale would be easier to read

Disable in manual - hard to imagine when you want to turn this on…

Max ISO - I think almost dispensable - when we have good control over the exposure time it is really the only remaing variable that decides about getting or not getting the picture

Allow underexposure: Allows the camera to underexpose instead of going over the computed Max exp. time (= better too dark than blurry)

* I usually disagree with Ken Rockwell, but nobody can be wrong all the time

AE-L Hold or EV-priority

May 4th, 2011

The Kodak Pony II* allowed to dial in the EV. You can do the same in some other way with your D90!

Set f4 to AE-L Hold

Obtain the exposure you want an press AE-L. The metered EV will be stored for some time (you can set the timeout via c2)

Easy Exposure compensation still works and you can vary the aperture in A-mode (or the speed in S-mode) and the D90 will compute the speed (or aperture) for you.

This helps in several situations where you’d consider shooting manual, but retains the convenience of adjusting aperture/speed by a single dial flip

I took me some minutes to learn it - embarrassing that I ignored this option for more than a year.

*Actually they cheated, the Pony II had a fixed shutter speed…But EV is easier to explain than Sunny 16.

Large aperture

May 4th, 2011

Nikon announced the AF-S 50mm f/1.8G. Not so long ago the f/1.4G was introduced. Is it worth it?

The slower lens is priced $220, the faster $480 - if this is already decisive, stop reading.

Read the rest of this entry »

DSLRs redesigned

May 4th, 2011

Nikonrumors is fun and I especially like the design studies they are writing about, like this one here: http://nikonrumors.com/2011/05/03/nikon-d5r-concept-camera.aspx

Besides our habit how our SLRs look like, is there room for improvement?

Let’s start to analyze why they look like the way they currently do. Of course the history is the 35mm camera:

  • Aspect 3:2 (100 year old tradition, Oskar_Barnack used this “hack” to get cheaply film for his new invention)
  • Room for the film rolls

For a SLR it turns out that the prism should be located on the long side of the frame to gain space. Look at you SLR and you understand. But wait: Read the rest of this entry »