Bloke Loc: Waynesboro, Pennsylvania

I took my camera out this evening for some test shots of houses all done up with Chtistmas lights. At some point, I want to go all around the place taking pictures of some of them, and I wondered if I needed to mess with a tripod or not.

So, handheld, camera set to Tv, shutter speed set to 1/80th of a second. I was shooting wide-angle and IS was on, so I figured that would be fast enough.

So, why did the camera use shutter speeds of nearly a full second - on one occasion, a full *15 seconds*???
The way the world used to work, if I said I wanted 1/80th, then I *got* 1/80th, even if it were completely under/over-exposed.

I don't understand what was going on here...

BHC Loc: Strawberry Valley, JF, USA

Bloke, have you checked pages 150 and 274 of your manual regarding automatic changes that may be made to Tv settings?

birdpix Loc: South East Pennsylvania

Bloke, some of the Canon cameras have what is called "safety shift" which will over ride your settings if the camera is unable to give you a good exposure in Tv or Av mode. It is one of the custom functions which you can turn on or off and it looks like you have it on.

It is designed to rescue you if the lighting suddenly changes dramatically. I suppose this could happen with Christmas lights blinking on and off etc.

mwsilvers Loc: Central New Jersey

Don't know the camera the OP has, but it sure sounds like safety shift took over.

BHC Loc: Strawberry Valley, JF, USA

For some silly reason, I thought Bloke had an SX50, but now I can't find anything about that now, so my answer was totally wrong and SHOULD BE IGNORED!

mwsilvers Loc: Central New Jersey

I thought he had a SX50 as well. Does the SX50 support safety shift or some similar feature? Perhaps he also has a Canon dslr.

rpavich Loc: West Virginia

Fuji's X cameras have this and it drives me nuts!

I shoot in manual alot to avoid this issue.

amehta Loc: Boston

This is shutter-PRIORITY mode, not shutter-lock. The first rule is that the camera will use the exposure it thinks is right, the second rule is it will use the shutter speed you selected if it can. With any sort of low light conditions, the maximum aperture of the lens becomes a physical limit. (That's why I shoot Av, not Tv, even for sports.)

In this situation, where there is no way the camera will get the exposure right, I agree with rpavich, use manual exposure mode. This is like shooting the moon: a point source which you want correctly exposed, not the scene it is dimly lighting.

Bloke Loc: Waynesboro, Pennsylvania

Thanks everyone! I only have a couple of seconds, but I wanted to acknowledge the help.

I *do* have an sx50 - I guess I have posted so much about that, I didn't want to labour the point. I will take a look at the manual this morning when I get home. It just threw me, and I was in a bit of a rush - dinner was in the oven, and I just wanted a quick walk down the street...

I still think that it should change anything else, rather than shutter speed, if I have Tv selected. I don't care about ISO or aperture in this case.

I suppose the test worked, in that it appears I will need the tripod - although I will run another test using manual and see if I can get it right. It would be a pain to have to keep dragging the tripod in and out of the car - it probably won't fit unless I fold the legs each time...

Anyway, thanks to all who responded. I will dig deeper into it when I get back from my morning session.

Dlevon Loc: New Jersey

I agree. Another example of not reading your manual thoroughly! What is it about humans!

Mick 53 Loc: Minneapolis

Where is the safety switch on a Canon 60d ? When using my ND filter with small ap and long exposure shooting in bright sunlight of a frozen lake the camera would not let me take the photo in manual.

windshoppe Loc: Arizona

I just got my SX50 and it DOES have the safety shift feature. You can disable it in the menu if it's currently on.

Bloke Loc: Waynesboro, Pennsylvania

Yeah, I remember seeing something about it in the book. I need to go back and read it again - thanks to the person who gave the page numbers, it is a pain to find anything in this manual!

I was aggravated, because that was the last chance I had to test the setup before today's rain and then tomorrow's arrival of the frigid air which the rest of the US has been 'enjoying' for a few days now. I am not always the most patient of people...

Bloke Loc: Waynesboro, Pennsylvania

I have read it... Not always easy to follow the dozens of 'see page N' comments in almost every section of the book! You have to remember, other than a "switch on, zoom and press the button" P&S, my last camera was a Canon A1. If you set it to Tv, then it would expose at the speed you told it. I made the error of believing that the newer Canons would do the same thing...

As far as 'safety shift' goes: It is not listed in the contents page. There is no index. It mentions it briefly on pp 150, and there is a paragraph about it on page 151 - but there is no heading or bold print to catch your eye if you were looking for it!

As an old programmer, I *always* read the manuals. If there is a printed manual with the product, I sit down and read it before I do anything else. I am not good with pdf manuals, but even after paying out to get this one printed out, it is really a POS as manuals go. There are dozens of pages describing such 'important' features as programming names and faces so the camera can recognise people, but not a lot about using it as a camera... The idea of a technical manula without an index is just bizarre!

GaryI Loc: NY & Fla

Interesting thread, I wasn't aware of this. Thanks.