iPhone 4 -- brightness settings

That's why keeping it at about 25 to 50% with auto brightness off is ideal, imo.

Autobrightness also isn't good on battery. It is constantly using the sensor to detect the light settings so it can adjust the screen brightness.

I keep my iPod touch 4 at about 15 to 25%.

The iPhone tends to adjust its brightness immediately when you unlock it. After that, I think it probably calculates an average ambient brightness in conjunction with the proximity sensor's data. Essentially, it'll more quickly respond to an increase in ambient brightness than a drop in ambient brightness (in general).

Basically, it will ignore a drop in brightness if there's something near to or covering the proximity sensor (e.g. your thumb when playing a racing game). An increase in ambient brightness (above that of the brightness measured at unlock), however, will usually result in a quick increase in display brightness for obvious reasons (there won't be anything covering the sensor during the increase).

I had a Samsung Galaxy S for a while and I noticed that it didn't use the proximity sensor to judge whether or not a drop in brightness was due to a thumb etc. Playing a lot of games in landscape, during which my thumb would cover the top of the phone as I held it, resulted in the display dimming... It was incredibly annoying.

EDIT: By the way, I leave my iPhone on just below 50% brightness with the auto-adjustment on. In my opinion, it gives the best balance between daytime visibility and use in low-light.

Hmm I just tested my iPhone 4 auto adjust to see if it is as you're saying and YES it is working slowly and wierd.

Ok it worked to go in a dark room to get lower brightness and a light room to get higher brightness and I tried to put it under a strong light then it did full brightness. But after that I went into a dark room with still full brightness haha wierd man! It takes about 10 seconds or so for mine to change...

Normally I never use the auto adjust. I do it myself as I need. Best solution hehe

[EDIT] : I have jailbroken mine to use SBsettings where you can adjust brightness very easy!

zelgit said:

Hmm I just tested my iPhone 4 auto adjust to see if it is as you're saying and YES it is working slowly and wierd.

Ok it worked to go in a dark room to get lower brightness and a light room to get higher brightness and I tried to put it under a strong light then it did full brightness. But after that I went into a dark room with still full brightness haha wierd man! It takes about 10 seconds or so for mine to change...

Normally I never use the auto adjust. I do it myself as I need. Best solution hehe

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As I suggested in my post above, a quick way to make the iPhone adjust to the ambient brightness is to lock and unlock it, especially when moving into a darker room or setting. That'll make it respond immediately to the change and is a bit quicker than going into the Settings app and changing it manually.

djr7572 said:

Interesting, I had always thought Autobrightness was better for the battery life because it's supposed to adjust based on your environment. Maybe it's just my phone, but Autobrightness has been rather worthless. I wonder if this is a common issue....?

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I've read that it gets brighter in the sunlight and dimmer in the dark. It's better to have the setting steady than have it constantly changing.

djr7572 said:

Which doesn't make any sense. Why would you want the screen dimmer in a dark room? Seems backward. On my my phone in particular, it wants to be dim in a dark room ... and if it ever does adjust itself, it's way after the fact. I don't know, mine is goofy to say the least. Very inconsistent in the way it behaves. I'm setting it myself from here on out ... hopefully it will equal better battery life rather than worse (I don't need the screen full bright, just bright enough so I can see it! Which Autobrightness is failing to do).

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Think about it. The display is backlit, not reflective, so if it were to get darker in sunlight, you wouldn't be able to see anything it's displaying. In the opposite scenario, if it were to get brighter in the dark, it would become really dazzling and straining for your eyes. The backlight should match the ambient brightness, in order to maintain a comfortable viewing clarity.

Auto brightness works remarkably well on mine. I have it on at all times, and have set the manual control to my preference in the daylight, then at night it adjusts to a very pleasant level in low light. I enjoy very good battery life as well.

djr7572 said:

I understand the logic. The brightness, ideally, should be just right and easy on the eyes. My phone just seems to make the display too dim every time I move into a darker room and I'm finding that to be straining. Maybe it's just not very good finding an optimum setting? Maybe it's just a weak point in my phone.

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I don't think it's specifically an issue with your phone. Whatever combo of sensor/algorithm they're using has been pretty worthless on all generations of the iPhone so far. And it's even worse on the iPad. I don't know anyone personally who uses it on either.

I JB'd and use SBSettings as well so I can adjust it quickly from any screen or app. Mine's typically around 30% indoors at home, closer to 50% under office-type lighting, and near max if I'm driving and using the iPod app in bright daylight. The times I've tried auto-brightness, it's ALWAYS too bright or too dark for comfortable viewing.