Hello guys, could u please tell me how much difference in terms of light arriving to a sensor would be if using a f1.2 lens versus using a f2.0 lens ? The camera specs says that it could achieve [email protected] (Color mode) / 0.0003Lux (Sense up) but instead I am going to mount on the camera a f2.0 lens. Could u please tell me which would be the correspondent lux achieved by the camera at f2.0 ? Thank you Re: F1.2 vs F2.0......how much light difference for lux ? Photographers don't worry about Lux values and instead consider stops. An f2.0 lens is about 1.5 stops slower than a f1.2 lens. We use stops because they are independent of things like sensor size and the physical aperture size. If we didn't use them we'd need to do very complicated maths every time we wanted to adjust exposure. This page explains how stops work. It's well worth reading it. http://www.fredparker.com/ultexp1.htm -- hide signature -- StephenG OP marcolisi • Regular Member • Posts: 247 Re: F1.2 vs F2.0......how much light difference for lux ? hi, thank u. I need this info for a camera that has these specs : Image Sensor 1/3" Super HAD II CCD Total Pixels 811(H) x 508(V) Effective Pixels 768(H) x 494(V) Scanning System 2 : 1 Interlace 525 Lines / 60 Fields / 30 Frames Synchronization Internal / Line Lock Scanning Frequency Horizontal : 15,734KHz / Vertical : 59.94Hz Horizontal Resolution 700TV Lines (Color) / 750 TV Lines (B/W) Min. Illumination [email protected] (Color mode) / 0.0003Lux (Sense up) S / N Ratio (Y signal) 52dB (AGC off, Weight on) Video Output 1.0Vp-p / 75 Ω (Video 0.714Vp-p, Sync 0.286Vp-p) OPERATION OSD Multi-language support Camera Title On / Off Day & Night True D/N ; Auto / Color / BW / Ext ICR (IR Cut Filter Removable) Yes WDR (Wide Dynamic Range) Low Frame; On / Off / Auto (WDR Lever, Weight) Digital Zoom On / Off selectable (1.0X ~ 10X) Back Light Compensation BLC, LWDR, HLC(ON/OFF) Gain Control Low / High / Off White Balance ATW(2,500K ~ 9,500 K)MANUAL/AWC Electronic Shutter Speed Auto / Normal (1/60 - 1/100,000) / Flickerless Sense-up (Frame Integration) On / Off (2X ~ 256X) RS-485 interface PELCO-D, PELCO-P protocol support Super DNR 3D-DNR Low / Middle / High / Off selectable Digital Image Stabilizer (DIS) On / Off Motion Detection On / Off(240 Block) Privacy Masking On / Off (8 Zones) Mirror / Flip Reverse Sharpness On / Off selectable (Level Adjustable) ENVIRONMENTAL Operating Temperature -20 C ~ +60 C Operating Humidity 10% ~ 80% RH MECHANICAL Ingress Protection N/A Dimensions 1.96(W) x 2.24(H) x 3.54(D) inch Weight 0.66 lb ELECTRICAL Power Source 24V AC / 12V DC (10%) Power Consumption Max. 150mA (at 12V DC) and the lens has these spes : Imager Size 1/3" Mount Type CS Focal Length 4mm Aperture F2.0 Iris Operation Auto Iris DC Focus Operation Manual Horizontal Field-of-View 1/4": 51.24 1/3": 68.47 Minimum Object Distance (M.O.D.) 30cm Filter Size N/A Dimensions (WxHxD) 1.5 x 1.7 x 2.6" (37 x 42 x 66mm) Weight 2.8 oz (79 g) any help please ? thank u  Marty4650 • Forum Pro • Posts: 16,374 I think you have come to the wrong place It seems like those specs are for a security CCTV camera, and this website is devoted to cameras and lenses for still photography or occasionally high end video. Someone here might be able to help you, but I think you do better if you found a CCTV forum.... -- Marty http://www.fluidr.com/photos/marty4650/sets/72157606210120132 http://www.flickr.com/photos/marty4650/sets/72157606210120132/show/ my blog: http://marty4650.blogspot.com/ Olympus E-30 Olympus E-P1 Panasonic LX100 Olympus OM-D E-M5 Olympus E-M1 Panasonic Lumix DMC-GM1 Panasonic Lumix DMC-GX85 +16 more trekkeruss • Veteran Member • Posts: 3,899 Re: F1.2 vs F2.0......how much light difference for lux ? What camera is it? It sounds like a video camera from those specs. Re: F1.2 vs F2.0......how much light difference for lux ? As other's pointed out this seems to be a video camera ( a CCTV camera I'd guess ). The simplest way to get your answer is to ask the maker. -- hide signature -- StephenG Johan Borg • Veteran Member • Posts: 3,506 Re: F1.2 vs F2.0......how much light difference for lux ? marcolisiwrote: It should be about 0.3 Lux if I understand the question correctly. The F1.2 lens in theory allows for almost 3 times more light to enter than the F2.0 lens: (2*2)/(1.2*1.2)=2.78 Sigma dp2 Quattro Sigma fp Sigma 45mm F2.8 DG DN OP marcolisi • Regular Member • Posts: 247 Re: F1.2 vs F2.0......how much light difference for lux ? Johan Borgwrote:marcolisiwrote: This is exactly the answer that I need. I really appreciate. The camera is a cctv camera, I tried writing everywhere, including cctv forums, but u were the only one coming up with an unswer that is exactly what I needed. Thank you so much. Could u pls explain me in detail how u came up with those numbers/math...I am just curious... Thank you Johan Borg • Veteran Member • Posts: 3,506 Re: F1.2 vs F2.0......how much light difference for lux ? marcolisiwrote:Johan Borgwrote: I'll try:
You may want to look up F-number on Wikipedia or something for a more precise explanation. This one is open for some nitpicking Sigma dp2 Quattro Sigma fp Sigma 45mm F2.8 DG DN OP marcolisi • Regular Member • Posts: 247 Re: F1.2 vs F2.0......how much light difference for lux ? Johan Borgwrote:marcolisiwrote:Johan Borgwrote: Thank you so much...so if I use a F2.5 lens I get : (2.5*2.5)(1.2*1.2)=4.34 so just a difference in 1/2 stop from a F2.0 lens to F2.5 lens gives me a difference in light of (4.34-2.78)= 1.56 ? It seems a big number....the F.2.0 lets to the sensor 1.56 times more light than the F2.5 Does it sound reasonable my math ? Thank you so much again for the instructions... GarageBoy • Contributing Member • Posts: 931 Re: F1.2 vs F2.0......how much light difference for lux ? Sounds about right Every stop is double, IIRC Johan Borg • Veteran Member • Posts: 3,506 Re: F1.2 vs F2.0......how much light difference for lux ? marcolisiwrote: Yes, except that the difference between F2.0 and F2.5 is more than a half stop. F2.0 is one stop larger than F2.8 which again is one stop larger than F4.0. Each stop is the previous f-number multiplied by the square root of 2. Sigma dp2 Quattro Sigma fp Sigma 45mm F2.8 DG DN OP marcolisi • Regular Member • Posts: 247 Re: F1.2 vs F2.0......how much light difference for lux ? I am really puzzled in wha to buy. I have 2 options:
or
Does the 150 dollars of difference really woth ? AnandaSim • Forum Pro • Posts: 13,425 Re: F1.2 vs F2.0......how much light difference for lux ? marcolisiwrote: This is a decision issue which cannot be solved by scientific discussion. It is like, "should I buy a Lamborghini or a top of the line Fiat" - both will take you there, one has more class certainly. Which one you buy depends on what? Whether you can afford a Lamb, whether you want to pay for a Lamb. Sure a Lamb is good, no doubt about it, but how good? Well, that is not the question. The question is, do you want to buy a Lamb? Kodak EasyShare P880 Olympus E-510 Olympus E-620 Panasonic Lumix DMC-G2 Olympus PEN E-PM2 +21 more OP marcolisi • Regular Member • Posts: 247 Re: F1.2 vs F2.0......how much light difference for lux ? Actually I think I need a lamborghini....my worries is if the lamborghini is really going to give me more than the fiat for the $$ I am spending... Does 150 dollars more sound a correct cost to pay for getting F2.0 over 2.5 ? Thank you AnandaSimwrote:marcolisiwrote: AnandaSim • Forum Pro • Posts: 13,425 Re: F1.2 vs F2.0......how much light difference for lux ? marcolisiwrote: There are some things in life that are linear scale based. For example, you can buy 500g, 1kg, 2kg of potatoes and it should be linear. With lenses, it is all curve, non linear f/4 lens is very cheap - easy to make, not much glass and perceived by the market to be budget f/2.8 lens - now that is what market recognise as a better than usual. So up the price - the maker decides the price not based on linear scale but how much will it hurt the sales volume f/2 - now we are playing for gold. The maker knows that this is a Lambhorgini. If you can afford one, no need to ask the price, ok, it is just pocket lint next to the cruise yacht you own for cruising the greek islands with your friend Bill Gates. Kodak EasyShare P880 Olympus E-510 Olympus E-620 Panasonic Lumix DMC-G2 Olympus PEN E-PM2 +21 more OP marcolisi • Regular Member • Posts: 247 Re: F1.2 vs F2.0......how much light difference for lux ? .I think I am going to go for the lamborghii... Thank you guys for all your help... Keyboard shortcuts: FForum MMy threads Latest sample galleriesLatest in-depth reviewsThe fourth camera in Leica's SL series of full-frame mirrorless cameras sees the 60MP BSI sensor from the Q3 and M11 models arrive with a significant interface redesign. The Fujifilm X100VI is the sixth iteration of Fujifilm's classically-styled large sensor compact. A 40MP X-Trans sensor, in-body stabilization and 6.2K video are among the updates. The Nikon Zf is a 24MP full-frame mirrorless camera with classic looks that brings significant improvements to Nikon's mid-price cameras. We just shot a sample reel to get a better feel for its video features and have added our impressions to the review. This $250 electronic lens adapter is perfect for Nikon Z-mount curious Sony shooters — shhh, we won’t tell anyone. Sony updates the ZV-1, giving the vlog-centric compact camera a 18-50mm equivalent F1.8-4.0 lens that's now wide enough for less cramped selfie mode videos. Latest buying guidesWhat's the best camera for travel? Good travel cameras should be small, versatile, and offer good image quality. In this buying guide we've rounded-up several great cameras for travel and recommended the best. If you want a compact camera that produces great quality photos without the hassle of changing lenses, there are plenty of choices available for every budget. Read on to find out which portable enthusiast compacts are our favorites. 'What's the best mirrorless camera?' We're glad you asked. What’s the best camera for around $2000? This price point gives you access to some of the most all-round capable cameras available. Excellent image quality, powerful autofocus and great looking video are the least you can expect. We've picked the models that really stand out. Above $2500 cameras tend to become increasingly specialized, making it difficult to select a 'best' option. We case our eye over the options costing more than $2500 but less than $4000, to find the best all-rounder. |
